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        <item>
            <title>Question 13 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p9</link>
            <description>Question 13 Exercise 6.2

Solutions of Question 13 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\mathrm{E}$$n=10$$m_1=4$$E, m_2=2$$L$$m_3=2$$C$\begin{align}\text{total number of permutations are}
 &amp;=\left(\begin{array}{c}
n \\
m_1, m_2, m_3
\end{array}\right)\\&amp;=\left(\begin{array}{c}
10 \\
4,2,2
\end{array}\right) \\
&amp; =\dfrac{10 !}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:41 +0000</pubDate>
        </item>
        <item>
            <title>Chapter 07: Permutation, Combination and Probability</title>
            <link>https://www.mathcity.org/fsc/fsc_part_1_solutions/ch07</link>
            <description>Chapter 07: Permutation, Combination and Probability

[Chapter 07: Permutation , Combination and Probability]
Notes (Solutions) of Chapter 07: Permutation , Combination and Probability, Text Book of Algebra and Trigonometry Class XI (Mathematics FSc Part 1 or HSSC-I), Punjab Text Book Board, Lahore.

Contents &amp; summary</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 26 Mar 2022 16:28:40 +0000</pubDate>
        </item>
        <item>
            <title>Definitions: FSc Part 1 (Mathematics): PTB</title>
            <link>https://www.mathcity.org/fsc-part1-ptb/definitions</link>
            <description>Definitions: FSc Part 1 (Mathematics): PTB

On this page, all the definitions of “Textbook of Algebra and Trigonometry Class XI, published by Punjab Textbook Board (PTB) Lahore, Pakistan are given. We are very thankful to Muhammad Waqas Sulaiman for his valuable contribution.$\frac{p}{q}$$p,q \in \mathbb{Z}$$q\neq 0$$\frac{p}{q}$$p,q \in \mathbb{Z}$$q\neq 0$$\mathbb{R}$$0.3333....,21.134134$$\pi = 3.1415...$$\divideontimes$$z=x+iy$$x,y \in \mathbb{R}, i = \sqrt{-1}$$x$$y$$z$$2, 3+\sqrt{3}i, \fra…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 22 Sep 2024 17:12:21 +0000</pubDate>
        </item>
        <item>
            <title>Chapter 06: Permutation, Combination and Probability</title>
            <link>https://www.mathcity.org/fsc/kpk_fsc_part_1/chapter_06_permutation_combination_and_probability</link>
            <description>Chapter 06: Permutation, Combination and Probability

Notes of Chapter 06: Permutation, Combination and Probability of “A Textbook of Mathematics for Class XI” published by Khyber Pakhtunkhwa (KPK) Textbook Board, Pesharwar. These notes are shared as open educational resources.</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 07 Feb 2021 16:47:22 +0000</pubDate>
        </item>
        <item>
            <title>FSc Part 1 (KPK Boards)</title>
            <link>https://www.mathcity.org/fsc/kpk_fsc_part_1</link>
            <description>FSc Part 1 (KPK Boards)

 These are the notes of old book. The notes of new book is AVAILABLE HERE 

[FSc Part 2 KPTP]
Notes of FSc Part 1 of “A Textbook of Mathematics For Class XI” published by Khyber Pakhtunkhwa Textbook Board, Peshawar. We are posting the notes chapter-wise. These notes are shared as open educational resources. This page will be continuously updated.$P(z)$$(\sum)$$\sum n$$\sum n^2$$\sum n^3$$n$$n$$$\frac{a}{a(a+d)}+\frac{a}{(a+d)(a+2d)}+...$$$^nP_r$$^nC_r=\left(\begin{smallm…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Tue, 12 Dec 2023 17:30:33 +0000</pubDate>
        </item>
        <item>
            <title>Unit 06: Permutation and Combination</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06</link>
            <description>Unit 06: Permutation and Combination

This is a sixth unit of the book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. On this page we have provided the solutions of the questions.$n$$n!$$n$$r$$n$$r$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 09 Mar 2025 10:56:17 +0000</pubDate>
        </item>
        <item>
            <title>Question 22 and 23, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p13</link>
            <description>Question 22 and 23, Exercise 6.2

Solutions of Question 22 and 23 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $(3\quad 4\quad 6\quad 1\quad 5\quad2)$$1$$2$$L=1, A=2, H=3, O=4, R=5, E=6$$(3,4,6,1,5,2)=$$(4\quad 6\quad 3\quad 2\quad 1\quad5)$$(4,6,3,2,1,5)$$4^{\text {th }}$$2^{\text {nd }}$$6^{\text {th }}$$3^{\text {rd }}$$3^{\text {rd…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:46 +0000</pubDate>
        </item>
        <item>
            <title>Unit 06: Permutation, Combination and Probability (Solutions)</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06</link>
            <description>Unit 06: Permutation, Combination and Probability (Solutions)

This is a sixth unit of the book Mathematics 11 published by Khyber Pakhtunkhwa Textbook Board, Peshawar, Pakistan. On this page we have provided the solutions of the questions.

After reading this unit the students will be able to$n$$n!$$n$$r$$^nP_r$$n$$r$$n$$r$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:34:51 +0000</pubDate>
        </item>
        <item>
            <title>A-Course of Mathematics (Paper A &amp; B)</title>
            <link>https://www.mathcity.org/bsc/paper_pattern/sargodha_university/a-course_of_mathematics</link>
            <description>A-Course of Mathematics (Paper A &amp; B)
This subject is consists of two papers of 100 marks each. One is called “Paper A” and other is called “Paper B”. This page is updated on February 15, 2015. This syllabus is for 1st Annual 2015 and onward organized by University of Sargodha, Sargodha.</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 07 Feb 2021 16:55:54 +0000</pubDate>
        </item>
        <item>
            <title>Ch 07: Permutation, Combination and Probability: Mathematics FSc Part 1</title>
            <link>https://www.mathcity.org/fsc/fsc_part_1_solutions/ch07/view</link>
            <description>Ch 07: Permutation, Combination and Probability: Mathematics FSc Part 1

Notes (Solutions) of Chapter 07: Permutation, Combination and Probability, Text Book of Algebra and Trigonometry Class XI (Mathematics FSc Part 1 or HSSC-I), Punjab Textbook Board (PTB), Lahore. There are eight exercises in this chapter. Please see the main page of this chapter for MCQs and important question at</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 26 Mar 2022 16:27:34 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 and 6 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p3</link>
            <description>Question 5 and 6 Exercise 6.2

Solutions of Question 5 and 6 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$7.$$7$$7$\begin{align}^7 P_7&amp;=\dfrac{7 !}{(7-7) !}\\
&amp; =7 !\\
&amp;=5,040 \end{align}$2,4,5,7,9$$2,4,5,7,9$$\mathrm{n} . \mathrm{m}$$e$$$=5.4 .3 .2=120\quad \text{or}$$$$^5 P_4=\dfrac{5 !}{5-4} !=120$$$2$$4$$3$$E_1$$m_1=2$$E_2$$m_2=3…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:36 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 &amp; 10 Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/re-ex6-p6</link>
            <description>Question 9 &amp; 10 Review Exercise 6

Solutions of Question 9 &amp; 10 of Review Exercise 6 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$2,3,0,3,4,2,3$$1$$=100,0000$$$=\dfrac{7 !}{3 ! \cdot 2 !}=420 $$$1$$0$$7$$0$$$=\dfrac{6 !}{2 ! 3 !}=60 $$$1$$420-50=360$$n$$n$$(n-1)$$(n - 1)$$(n-1)$$(n-2) !$$2$$2 !$$n$$$(n-2) ! \cdot 2 !=2(n-2) ! $$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:03 +0000</pubDate>
        </item>
        <item>
            <title>Exercise 6.2 (Solutions)</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2</link>
            <description>Exercise 6.2 (Solutions)

The solutions of the Exercise 6.1 of book “Model Textbook of Mathematics for Class XI” published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan are given on this page. This exercise consists of the question related to factorial function.$n!$$$
n!=\left\{\begin{array}{l}
n(n-1)(n-2)\cdot \ldots \cdot 3 \cdot 2 \cdot 1 \text{ if } n\geq 1,\\
1 \text{ if } n=0.
\end{array} \right.
$$$n \in \mathbb{N}$${ }^n P_r=\frac{n!}{(n-r)!}$$\quad{ }^…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:59 +0000</pubDate>
        </item>
        <item>
            <title>Question 10 and 11, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p7</link>
            <description>Question 10 and 11, Exercise 6.2

Solutions of Question 10 and 11 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $=6$$={ }^{6}{ }^{1} P_{5}=6$$720$$F$$F$$5$$5!=120$$=9$$S=2$$T=2$$A=2$\begin{align*}\text{possible permutation}&amp;=\dfrac{9!}{2!2!2!}\\
&amp;=\dfrac{362880}{8}\\
&amp;=45360\end{align*}</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:56 +0000</pubDate>
        </item>
        <item>
            <title>Multiple Choice Questions (MCQs)</title>
            <link>https://www.mathcity.org/fsc-part1-kpk/mcqs</link>
            <description>Multiple Choice Questions (MCQs)

Here are the sample MCQs at this time. Page will be updated periodically. 

SAMPLE MCQs

	*  $i^{13}=$.............
		*  (A) $i$
		*  (B) 1
		*  (C) -1
		*  (D) 2

	*  Set of all possible subsets of $S$ is called
		*  (A) Equivalent sets$1, \omega, \omega^2$$-1, \omega, \omega^2$$-1, -\omega, -\omega^2$$1, -1, 2$$ax^2+bx+c=0$$a=0, b\neq 0$$a\neq 0$$a=b=0$$b=$$ax^2+bx+c=0$$a=0, b\neq 0$$a\neq 0$$a=b=0$$b=$$n!=n(n-1)(n-2)...3\cdot 2\cdot 1$$n$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 28 Aug 2023 17:03:58 +0000</pubDate>
        </item>
        <item>
            <title>Important Questions: HSSC-I</title>
            <link>https://www.mathcity.org/fsc-part1-ptb/important-questions</link>
            <description>Important Questions: HSSC-I

[Important Questions FSc/ICS Part 1]
These are the important questions for “Textbook of Algebra and Trigonometry Class XI” published by Punjab Textbook Board (PTB) Lahore, Pakistan. These questions are taken from old papers. These are very helpful to understand the types of questions which may asked final paper of mathematics for FSc/ICS (HSSC) Part 1. Lot of energy has been put to collect and write these questions. These are taken from old papers of FBISE Islamabad,…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 18 Apr 2024 08:01:02 +0000</pubDate>
        </item>
        <item>
            <title>Multiple Choice Questions (MCQs)</title>
            <link>https://www.mathcity.org/math-11-kpk/mcqs</link>
            <description>Multiple Choice Questions (MCQs)

Here are the sample MCQs at this time. Page will be updated periodically. 

SAMPLE MCQs

	*  $i^{13}=$.............
		*  (A) $i$
		*  (B) 1
		*  (C) -1
		*  (D) 2

	*  Set of all possible subsets of $S$ is called
		*  (A) Equivalent sets$1, \omega, \omega^2$$-1, \omega, \omega^2$$-1, -\omega, -\omega^2$$1, -1, 2$$ax^2+bx+c=0$$a=0, b\neq 0$$a\neq 0$$a=b=0$$b=$$ax^2+bx+c=0$$a=0, b\neq 0$$a\neq 0$$a=b=0$$b=$$n!=n(n-1)(n-2)...3\cdot 2\cdot 1$$n$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Tue, 05 Dec 2023 02:44:44 +0000</pubDate>
        </item>
        <item>
            <title>Mathematical Statistics by Ms. Iqra Liaqat</title>
            <link>https://www.mathcity.org/notes/mathematical-statistics-iqra-liaqat</link>
            <description>Mathematical Statistics by Ms. Iqra Liaqat

[Mathematical Statistics by Ms. Iqra Liaqat]

These notes are send by Ms. Iqra Liaqat. We are really very thankful to her for providing these notes and appreciates her effort to publish these notes on MathCity.org
 Name  Mathematical Statistics   Provided by</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 20 Apr 2023 12:30:11 +0000</pubDate>
        </item>
        <item>
            <title>Quantitative Reasoning-I (QR1: Exploring Quantitative Skills)</title>
            <link>https://www.mathcity.org/notes/qr1-exploring-quantitative-skills-m-usman-hamid</link>
            <description>Quantitative Reasoning-I (QR1: Exploring Quantitative Skills)

[Quantitative Reasoning-I (Exploring Quantitative Skills)  by M Usman Hamid]
This handout offers a comprehensive introduction to numeracy and quantitative reasoning, laying a solid foundation for analytical thinking.  It explores fundamental concepts, from basic arithmetic and unit analysis to more advanced topics like probability and statistics.  A unique highlight is its exploration of the contributions of mathematicians and statis…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 15 Dec 2025 16:47:25 +0000</pubDate>
        </item>
        <item>
            <title>Chapter 02: Groups</title>
            <link>https://www.mathcity.org/bsc/notes_of_mathematical_method/ch02_groups</link>
            <description>Chapter 02: Groups

[Chapter 02: Groups]
Notes of the book Mathematical Method written by S.M. Yusuf, A. Majeed and M. Amin, published by Ilmi Kitab Khana, Lahore - PAKISTAN.

Contents and summary

	*  Definition (axioms of group)
	*  Definition ( commutative group )
	*</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Mon, 11 Dec 2023 13:00:23 +0000</pubDate>
        </item>
        <item>
            <title>Ch 07: Permutation, Combination and Probability</title>
            <link>https://www.mathcity.org/fsc-part1-ptb/important-questions/ch07-permutation-combination-and-probablity</link>
            <description>Ch 07: Permutation, Combination and Probability

	*  Find $n$ when ${^nC_{12}}={^nC_6}$ --- BISE Gujranwala(2015)
	*  Evaluate  ${^{20}C_{17}}$ without calculator --- BISE Gujranwala(2015)
	*  How many $6-digit$ numbers can be formed from the digits $2,2,3,3,4,4$? How many of them with lie between $400,000$ and $430,000$?  ---$``PLANE&quot;$$^nC_4=^nC_{n-r}$$6-digits$$n^3-n$$6$$n=2,3$$n$$^nP_2=30$$6-dided$$n$$^nC_{12}=^nC_6$$^{n-1}C_r+^{n-1}C_{r-1}=^nC_r$$\frac{a_5}{a_3}=\frac{4}{9}$$a_2=\frac{4}{9}$…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 07 Feb 2021 16:47:42 +0000</pubDate>
        </item>
        <item>
            <title>MCQs with Answers (FSc/ICS Part 1)</title>
            <link>https://www.mathcity.org/fsc/fsc_part_1_mcqs/mcqs_with_answers</link>
            <description>MCQs with Answers (FSc/ICS Part 1)

[MCQs Choice]
In this one PDF, MCQs of all chapters of FSc/ICS Part1 are given. There are seven chapters. Answers of MCQs is starting from page 71.

SAMPLE MCQs

	*  $i^{13}=$.............
		*  (A) $i$
		*  (B) 1
		*  (C) -1
		*  (D) 2

	* $S$$1, \omega, \omega^2$$-1, \omega, \omega^2$$-1, -\omega, -\omega^2$$1, -1, 2$$ax^2+bx+c=0$$a=0, b\neq 0$$a\neq 0$$a=b=0$$b=$$ax^2+bx+c=0$$a=0, b\neq 0$$a\neq 0$$a=b=0$$b=$$n!=n(n-1)(n-2)...3\cdot 2\cdot 1$$n$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 02 May 2024 17:03:11 +0000</pubDate>
        </item>
        <item>
            <title>Pure Mathematics (Paper A &amp; B)</title>
            <link>https://www.mathcity.org/bsc/paper_pattern/sargodha_university/pure_mathematics</link>
            <description>Pure Mathematics (Paper A &amp; B)

This paper consist of two papers of 100 marks each. One paper is called “Paper A” and the other is called “Paper B”.

Paper A

	*  NOTE: attempt two questions from each section.

SECTION-I (4/12: 17,17,17,17)</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 07 Feb 2021 16:55:59 +0000</pubDate>
        </item>
        <item>
            <title>View Online (Solutions of Chapter 07)</title>
            <link>https://www.mathcity.org/fsc/fsc_part_1_solutions/ch07/viewer</link>
            <description>View Online (Solutions of Chapter 07)

Notes (Solutions) of Chapter 07: Permutation , Combination and Probability, Text Book of Algebra and Trigonometry Class XI (Mathematics FSc Part 1 or HSSC-I), Punjab Text Book Board, Lahore.



Here is the list of all exercises of Chapter 07</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sun, 07 Feb 2021 16:57:56 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 and 2 Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-1-p1</link>
            <description>Question 1 and 2 Exercise 6.1

Solutions of Question 1 and 2 of Exercise 6.1 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\dfrac{10 !}{3 ! .3 ! \cdot 4 !}$\begin{align}\dfrac{10 !}{3 ! \cdot 3 ! \cdot 4 !}&amp;=\dfrac{10.9 .8 \cdot 7 \cdot 6 \cdot 5.4 !}{3 ! \cdot 3 ! \cdot 4 !}\\
&amp;=\dfrac{10.9 .8 .7 .5}{3.2 .1}\\
&amp;=4200 \end{align}$\dfrac{3 !+4 !}{5 !-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:32 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 &amp; 4 Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-1-p2</link>
            <description>Question 3 &amp; 4 Exercise 6.1

Solutions of Question 3 &amp; 4 of Exercise 6.1 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\dfrac{1}{6 !}+\dfrac{2}{7 !}+\dfrac{3}{8 !}=\dfrac{75}{8 !}$\begin{align}\dfrac{1}{6 !}+\dfrac{2}{7 !}+\dfrac{3}{8 !}&amp;=\dfrac{1}{6 !}+\dfrac{2}{7.6 !}+\dfrac{3}{8.7 .6 !} \\
&amp; =\dfrac{56+16+3}{8 !}\\
&amp;=\dfrac{75}{8 !}\end{align}$\df…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:30 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-1-p3</link>
            <description>Question 5 Exercise 6.1

Solutions of Question 5 of Exercise 6.1 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\dfrac{(2 n) !}{n !}=2^n(1.3 .5 \ldots(2 n-1))$\begin{align}\dfrac{(2 n) !}{n !}&amp;=\dfrac{1}{n !}[(2 n)(2 n-1)(2 n-2) \\
&amp;=(2 n-3)(2 n-4)(2 n-5) \ldots(2 n-(2 n-4))\\
&amp;(2 n-(2 n-3))(2 n-(2 n-2))(2 n-(2 n-1))]\end{align}$2 n$\begin{align}\dfra…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:32 +0000</pubDate>
        </item>
        <item>
            <title>Question 4 Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-1-p4</link>
            <description>Question 4 Exercise 6.1

Solutions of Question 4 of Exercise 6.1 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:33 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-1-p5</link>
            <description>Question 5 Exercise 6.1

Solutions of Question 5 of Exercise 6.1 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:33 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 and 2 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p1</link>
            <description>Question 1 and 2 Exercise 6.2

Solutions of Question 1 and 2 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$^6 P_6$\begin{align}^6 P_6&amp;=\dfrac{6 !}{(6-6) !}\\
&amp;=6 !=720\end{align}$^{20} P_2$\begin{align}^{20} P_2&amp;=\dfrac{20 !}{(20-2) !}\\
&amp;=\dfrac{20.19 .18 !}{18 !}\\
&amp;=20 \times 19=380\end{align}$^{16} P_3$\begin{align}^{16} P_3&amp;=\dfr…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:35 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 and 4 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p2</link>
            <description>Question 3 and 4 Exercise 6.2

Solutions of Question 3 and 4 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$^n P_r=n(^{n-1} P_{r-1})$$$^n P_r=n({ }^{n-1} P_{r-1})$$\begin{align}n(^{n-1} P_{r-1})&amp;=n \dfrac{(n-1) !}{((n-1)-(r-1)) !} \\
&amp; =\dfrac{n(n-1) !}{(n-r) !}\\
&amp;=\dfrac{n !}{(n-r) !}\\
&amp;=^n P_r\end{align}$^n P_r=^{n-1} P_r+r(^{n-1} …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:37 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 and 8 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p4</link>
            <description>Question 7 and 8 Exercise 6.2

Solutions of Question 7 and 8 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$1,2,3,4$$E_1$$m_1=5$$E_2$$\cdot m_2=5$$E_3$$m_3=5$$$m_1 \cdot m_2 \cdot m_3=5.5 \cdot 5=125$$$1,2,3,4$$E_1$$m_1=5$$E_2$$m_2=4$$E_3$$m_3=3$$$m_1 \cdot m_2 \cdot m_3=5 \cdot 4 \cdot 3=60$$$8$$5$$=4$$=4$$=5$$=3$$4 ! \cdot 5 ! \cdot …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:38 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p5</link>
            <description>Question 9 Exercise 6.2

Solutions of Question 9 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$=^6 P_1=6$$s=^6 P_2=30$$=^6 P_3=120$$=^6 P_4=360$$=^6 P_5=720$$=^6 P_6=720$$6+30+120+360+720+720=1956$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:38 +0000</pubDate>
        </item>
        <item>
            <title>Question 10 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p6</link>
            <description>Question 10 Exercise 6.2

Solutions of Question 10 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$n=8$$r=5$\begin{align}^8 P_5&amp;=\dfrac{8 !}{(8-5) !}\\
&amp;=\dfrac{8 \cdot 7 \cdot 6 \cdot 5 \cdot 4 \cdot 3 !}{3 !}\\
&amp;=6720\end{align}\begin{align}^2 P_2 \times^7 P_4&amp;=2 \times \dfrac{7 !}{(7-4) !}\\
&amp;=2 \times\dfrac{7.6 .5 .4 .3 !}{3 !}\\
&amp;=…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:40 +0000</pubDate>
        </item>
        <item>
            <title>Question 11 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p7</link>
            <description>Question 11 Exercise 6.2

Solutions of Question 11 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$10$$1000$$2.3,4,0,8,9$$10$$1000$$10$$100$$E_1$$m_1=5$$E_2$$m_2=5$$10$$100$$$m_1 \cdot m_2=5.5=25$$$100$$1000$$0$$E_1$$m_1=5$$E_2$$\boldsymbol{m}_2=5$$E_3$$m_3=4$$100$$1000$$$m_1 \cdot m_2 \cdot m_3=5.5 \cdot 4=100$$$10$$1000$$$100 + 25=125…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:40 +0000</pubDate>
        </item>
        <item>
            <title>Question 12 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p8</link>
            <description>Question 12 Exercise 6.2

Solutions of Question 12 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$8.$$n=8$$\mathrm{O}$$m_1=3$\begin{align}
 \left(\begin{array}{c}
n \\
m 1
\end{array}\right)&amp;=\left(\begin{array}{l}
8 \\
3
\end{array}\right) \\
&amp; =\dfrac{8 !}{3 !}\\
&amp;=\dfrac{8 \cdot 7 \cdot 6 \cdot 5 \cdot 4 \cdot 3 !}{3 !}\\
&amp;=6,720 \e…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:41 +0000</pubDate>
        </item>
        <item>
            <title>Question 14 and 15 Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-2-p10</link>
            <description>Question 14 and 15 Exercise 6.2

Solutions of Question 14 and 15 of Exercise 6.2 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$$\dfrac{(n-1) !}{2}=\dfrac{(5-1) !}{2}=\dfrac{24}{2}=12 $$$7$$7$$6 !$$6$$5!$$2 !=2$$7$$$2 \times 5 !=240$$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:35 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-3-p1</link>
            <description>Question 1 Exercise 6.3

Solutions of Question 1 of Exercise 6.3 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$^n C_2=36$$n$\begin{align}&amp;^n C_2=36\\
&amp; \Rightarrow \dfrac{n !}{(n-2) ! 2 !}=36 \\
&amp; \Rightarrow \dfrac{n(n-1)(n-2) !}{(n-2) ! \cdot 2}=36 \\
&amp; \Rightarrow n(n-1)=72 \\
&amp; \Rightarrow n^2-n-72=0 \\
&amp; \Rightarrow n^2-9 n+8 n-72=0\\
&amp; \Rightar…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:43 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-3-p2</link>
            <description>Question 2 Exercise 6.3

Solutions of Question 2 of Exercise 6.3 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$n$$r$${ }^n P_r=840$${ }^n C_r=35$\begin{align}
&amp;^n P_r=\dfrac{n !}{(n-r) !}=840 ....(i)\\
&amp;^n C_r=\dfrac{n !}{(n-r) ! r !}=35....(ii)\end{align}\begin{align}\dfrac{n !}{(n-r) !} \cdot \dfrac{(n-r) ! r !}{n !}&amp;=\dfrac{840}{35}\\
r!&amp;=24\\
\te…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:43 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-3-p3</link>
            <description>Question 3 Exercise 6.3

Solutions of Question 3 of Exercise 6.3 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$n$$^{2 n} C_3:^n C_2=36: 3$\begin{align}
&amp; { }^{2 n} C_3:{ }^n C_2=36: 3 . \\
&amp; \Rightarrow \dfrac{(2 n) !}{(2 n-3) ! 3 !} \times \dfrac{(n-2) ! 2 !}{n !}=12 \\
&amp; \Rightarrow \dfrac{2 n(2 n-1)(2 n-2)(2 n-3) !}{(2 n-3) ! 3 !}\times\dfrac{(n-2…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:45 +0000</pubDate>
        </item>
        <item>
            <title>Question 4 Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-3-p4</link>
            <description>Question 4 Exercise 6.3

Solutions of Question 4 of Exercise 6.3 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.${ }^{n-1} C_r+{ }^{n-1} C_{r-1}={ }^n C_r$$${ }^n{ }^1 C_r+{ }^n{ }^1 C_{r-1}={ }^n C_s$$\begin{align}
{ }^{n-1} C_r+{ }^{n-1} C_{r-1}&amp;=\dfrac{(n-1) !}{(n-r-1) ! r !}+\dfrac{(n-1) !}{(n-1-(r-1)) !(r-1) !} \\
&amp; =\dfrac{(n-1) !}{(n-r-1) ! r(r-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:46 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 and 6 Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-3-p5</link>
            <description>Question 5 and 6 Exercise 6.3

Solutions of Question 5 and 6 of Exercise 6.3 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$12$$n=12$${ }^{12} C_2=66$$12$$n=12$${ }^{12} C_3=220$$${ }^6 C_2=\dfrac{6 !}{(6-2) ! 2 !}=15 $$$6$$\quad 15-6=9$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:46 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 and 8 Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-3-p6</link>
            <description>Question 7 and 8 Exercise 6.3

Solutions of Question 7 and 8 of Exercise 6.3 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$20$\begin{align}{ }^{20} C_2&amp;=\dfrac{20 !}{(20-2)2!}!\\
&amp;=\dfrac{20!}{18!\cdot 2!}\\
&amp;=190\end{align}$7$$10$$3$$7$$10$$${ }^{10} C_7=\dfrac{10 !}{(10-7) ! 7 !}=120$$$7$$4.$$4$$${ }^7 C_4=\dfrac{7 !}{(7-4) ! 4 !}=35.$$$35$$10.$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:47 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-3-p7</link>
            <description>Question 9 Exercise 6.3

Solutions of Question 9 of Exercise 6.3 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$8$$6$$7$$7$$6.$$=7+6=13$${ }^7 C_4$${ }^6 C_4$\begin{align}{ }^7 C_4 \cdot{ }^6 C_4&amp;=\dfrac{7 !}{(7-4) ! 4 !} \cdot \dfrac{6 !}{(6-4)}\\\
&amp;= 525\end{align}$8$$6$$7$$7$$6$$=7+6=13$$3,4,5,6$$6$\begin{align}{ }^7 C_2 \cdot{ }^6 C_6&amp;=\dfrac{7 !}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:48 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-3-p8</link>
            <description>Question 9 Exercise 6.3

Solutions of Question 9 of Exercise 6.3 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:48 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 Exercise 6.4</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-4-p1</link>
            <description>Question 1 Exercise 6.4

Solutions of Question 1 of Exercise 6.4 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$S=\{1,2,3,4,5,6\}$$5$$5$\begin{align}A&amp;=\{5\}\\
P(A)&amp;=\dfrac{n(A)}{n(S)}\\
&amp;=\dfrac{1}{6} \end{align}$S=\{1,2,3,4,5,6\}$$1$$1$\begin{align}B&amp;=\{\}\\
&amp;=\phi \text{then}\\
P(B)&amp;=\dfrac{n(B)}{n(S)}\\
&amp;=\dfrac{0}{6}\\
&amp;=0\end{align}$S=\{1,2,3,4,…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:49 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 Exercise 6.4</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-4-p2</link>
            <description>Question 2 Exercise 6.4

Solutions of Question 2 of Exercise 6.4 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$4$$5$$6$$3$$4+5+6=15$$${ }^{15} C_3=\dfrac{15 !}{(15-3) ! 3 !}=455 $$$${ }^6 C_4=\dfrac{6 !}{(6-4) ! 4 !}=15$$$$=\dfrac{15}{455}=\dfrac{3}{91}$$$4$$5$$6$$3$$4+5+6=15$$${ }^{15} C_3=\dfrac{15 !}{(15-3) ! 3 !}=455 $$$${ }^4 C_3=\dfrac{4 !}{(4-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:50 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 Exercise 6.4</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-4-p3</link>
            <description>Question 3 Exercise 6.4

Solutions of Question 3 of Exercise 6.4 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$8$$8$$2^8$$$n(S)=256$$$$\dfrac{1}{256}$$$8$$$A=\{8\}$$$${ }^8 C_8=\dfrac{8 !}{(8-8) ! 8 !}=1$$$8$$$P(A)=\dfrac{1}{256}$$$7$$8$$2^8$$$n(S)=256$$$$\dfrac{1}{256}$$$7$$$B=\{7\}$$$7$$8$$$n(B)={ }^8 C_7=\dfrac{8 !}{(8-7) ! 7 !}=8$$$7$$8$$$P(B)=\d…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:51 +0000</pubDate>
        </item>
        <item>
            <title>Question 4 Exercise 6.4</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-4-p4</link>
            <description>Question 4 Exercise 6.4

Solutions of Question 4 of Exercise 6.4 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.\begin{align}S&amp;=(HHII,HHT.HTH.HTT.THII.THT.TTH,TT7),\\
\text{then} n(S)&amp;=2^3=8\end{align}$$A=\{H H H\}$$$$n(A)=1$$$P(A)=\dfrac{n(A)}{n(S)}=\dfrac{1}{8}$\begin{align}S&amp;=(HHII,HHT.HTH.HTT.THII.THT.TTH,TT7),\\ 
\text{then} n(S)&amp;=2^3=8\end{align}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:52 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 Exercise 6.4</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-4-p5</link>
            <description>Question 5 Exercise 6.4

Solutions of Question 5 of Exercise 6.4 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$6$$4$$3$$2$$=6+4=10$$5$$10$\begin{align}{ }^{10)} C_5 &amp;=\dfrac{10 !}{(10-5) ! 5 !}\\
&amp;=252\\ 
n(S)&amp;=252\end{align}$3$$2$$3$$2$\begin{align}{ }^6 \mathrm{C}_3\cdot{ }^{4} \mathrm{C}_2&amp;=\dfrac{6 !}{(6-3) ! 3 !} \cdot \dfrac{4 !}{(4-2) ! 2 !}\\…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:52 +0000</pubDate>
        </item>
        <item>
            <title>Question 6 Exercise 6.4</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-4-p6</link>
            <description>Question 6 Exercise 6.4

Solutions of Question 6 of Exercise 6.4 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$52$$$=52$$$=4$$$=\dfrac{4}{52}=\dfrac{1}{13}$$$52$$=52$$13$$13$$$\dfrac{13}{52}+ \dfrac{13}{52}=\dfrac{1}{4}+\dfrac{1}{4}=\dfrac{2}{4}=\dfrac{1}{2}$$$52$$=52$$13.$$$=\dfrac{13}{52}=\dfrac{1}{4}$$$52$$=52$$12.$$$=\dfrac{12}{52}=\dfrac{3}{13}$…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:53 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 Exercise 6.4</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-4-p7</link>
            <description>Question 7 Exercise 6.4

Solutions of Question 7 of Exercise 6.4 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.\begin{align}S&amp;=\{(i, j) ; i, j=1,2,3,4,5,6\}\\
&amp;=\left[\begin{array}{llllll}
(1,1) &amp; (1,2) &amp; (1,3) &amp; (1,4) &amp; (1,5) &amp; (1,6) \\
(2,1) &amp; (2,2) &amp; (2,3) &amp; (2,4) &amp; (2,5) &amp; (2,6) \\
(3,1) &amp; (3,2) &amp; (3,3) &amp; (3,4) &amp; (3,5) &amp; (3,6) \\
(4,1) &amp; (4,2) &amp; (…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:53 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 and 2 Exercise 6.5</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-5-p1</link>
            <description>Question 1 and 2 Exercise 6.5

Solutions of Question 1 and 2 of Exercise 6.5 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$A$$B$$P(A)=\dfrac{2}{5}, P(B)=\dfrac{2}{5}$$P(A \cup B)=\dfrac{1}{2}$$P(A \cap B)$\begin{align}
 P(A \cup B)&amp;=P(A)+P(B)-P(A \cap B) \\
 \Rightarrow P(A \cap B)&amp;=P(A)+P(B)-P(A \cup B)
\end{align}$P(A), P(B)$$P(A \cup B)$$$P(A \cap…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:54 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 and 4 Exercise 6.5</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-5-p2</link>
            <description>Question 3 and 4 Exercise 6.5

Solutions of Question 3 and 4 of Exercise 6.5 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$P(A)=0.5$$P(A \cup B)=0.6$$P(B)$$A$$B$$\mathrm{A}$$B$$A \cap B=\emptyset$\begin{align}P(A \cup B)&amp;=P(A)+P(B)\\
\Rightarrow P(B)&amp;=P(A \cup B)-P(A)\\
&amp;=0.6-.0 .5=0.1 \end{align}$30$$1$$30.$\begin{align}S&amp;=\{1,2,3, \ldots, 50\} \tex…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:55 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 and 6 Exercise 6.5</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-5-p3</link>
            <description>Question 5 and 6 Exercise 6.5

Solutions of Question 5 and 6 of Exercise 6.5 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\dfrac{8}{9}$$$E=\{ event\, passing\, the\, test \}$$$$E^{\prime}=\{ event\, failing\, the\, test \}$$$E$$E^{\prime}$$P(E)=\dfrac{8}{9}$\begin{align}P(E^{\prime})&amp;=1-P(E)=1-\dfrac{8}{9}=\dfrac{1}{9}\end{align}$4$$4$\begin{align}S…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:56 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 Exercise 6.5</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-5-p4</link>
            <description>Question 7 Exercise 6.5

Solutions of Question 7 of Exercise 6.5 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$52$$52$$26$$26$$13$$13$$13$$13$$13$$10,9,8,7,6,5,4,3$$2.$$$=\dfrac{13}{52}=\dfrac{1}{4}$$$$=\dfrac{4}{52}=\dfrac{1}{13}$$\begin{align}
P(A \cup B)&amp;=P(A)+P(B) \\
&amp; =\dfrac{1}{4}+\dfrac{1}{13}=\dfrac{17}{52} \end{align}$$=1-\dfrac{17}{52}=\dfr…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:56 +0000</pubDate>
        </item>
        <item>
            <title>Question 8 Exercise 6.5</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-5-p5</link>
            <description>Question 8 Exercise 6.5

Solutions of Question 8 of Exercise 6.5 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$7$$11.$\begin{align}s&amp;=(i i, j): i, j-1,2,3,4,5,6\}\\
&amp;=\left[\begin{array}{llllll}
(1.1) &amp; (1.2) &amp; (1.3) &amp; (1.4) &amp; (1.5) &amp; (1.6) \\
(2.1) &amp; (2.2) &amp; (2.3) &amp; (2.4) &amp; (2.5) &amp; (2.6) \\
(3.1) &amp; (3.2) &amp; (3.3) &amp; (3.4) &amp; (3.5) &amp; (3.6) \\
(4.1) &amp; (4…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:57 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 Exercise 6.5</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-5-p6</link>
            <description>Question 9 Exercise 6.5

Solutions of Question 9 of Exercise 6.5 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$2$$\dfrac{1}{7}$$\dfrac{1}{5}$\begin{align}
P(\text { Ajmal scicction })&amp;=\dfrac{1}{7} \\
\Rightarrow P(\text { Ajmal not selected })&amp;=\dfrac{6}{7} \\
P(\text { Bushra selection })&amp;=\dfrac{1}{5} \\
\Rightarrow P(\text { Bushra not selected }…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:57 +0000</pubDate>
        </item>
        <item>
            <title>Question 10 Exercise 6.5</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/ex6-5-p7</link>
            <description>Question 10 Exercise 6.5

Solutions of Question 10 of Exercise 6.5 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$20$$10$$5$$3$$2$$=20$$=10$$=5$$=3$$=15$$=5$$=10$$=3$$=22$$E$$a A$$B$$2$\begin{align}n(S)&amp;={ }^{30} C_2\\
&amp;=435\\
P(A)&amp;=\dfrac{^{20} C_2}{^{30} C_2}\\
&amp;=\dfrac{190}{435}=\dfrac{38}{87}\\
P(B)&amp;=\dfrac{^{22} C_2}{^{30} C_2}\\
&amp;=\dfrac{231}{43…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:58 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/re-ex6-p1</link>
            <description>Question 1 Review Exercise 6

Solutions of Question 1 of Review Exercise 6 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$O, P, Q, R, S, T, U$$2520$$9040$$5140$$4880$$2520$$\{1,2,3,4,5,6,7\}$$14$$42$$28$$21$$28$$\{1,2,3,4,6,7,8\}$$3$$7$$120$$180$$144$$96$$120$$\dfrac{(n+2) !(n-2) !}{(n+1) !(n-1) !}$$(n-3)$$(\dot{n}-1)$$\dfrac{n+1}{n+2}$$\dfrac{n+2}{n-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:35:59 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/re-ex6-p2</link>
            <description>Question 2 Review Exercise 6

Solutions of Question 2 of Review Exercise 6 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.${ }^{2 n} C_r={ }^{2 n} C_{r+2}$$r$\begin{align}
{ }^{2 n} C_r&amp;={ }^{2 n} C_{r+2} \\
\Rightarrow \dfrac{(2 n) !}{(2 n-r) ! r !}&amp;=\dfrac{(2 n) !}{(2 n-(r+2)) !(r+2) !}\end{align}$(2 n)$\begin{align}
\Rightarrow \dfrac{1}{(2 n-r) ! r…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:00 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 &amp; 4 Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/re-ex6-p3</link>
            <description>Question 3 &amp; 4 Review Exercise 6

Solutions of Question 3 &amp; 4 of Review Exercise 6 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.${ }^{56} P_{r+6}:{ }^{54} P_{r+3}=30800: 1$$r$\begin{align}
{ }^{56} P_{r+6}:{ }^{54} P_r+3&amp;=30800: 1  \\
\Rightarrow \dfrac{\dfrac{56 !}{[56-(r+6)] !}}{\dfrac{54 !}{[54-(r+3)] !}}&amp;=\dfrac{30800}{1} \\
\Rightarrow \dfrac{56…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:00 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 &amp; 6 Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/re-ex6-p4</link>
            <description>Question 5 &amp; 6 Review Exercise 6

Solutions of Question 5 &amp; 6 of Review Exercise 6 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$$n=6$$$$(n-1) !=(6-1) !=5 !=120$$$120-24=96$$n=6$$(n-1) !=(6-1) !=5 !=120$$$(n-1) !=(5-1) !=4 !=24$$$$(n-1) !=(6-1) !=5 !=120$$$$4 ! \cdot 2 !=48$$$(5-1) !$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:01 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 &amp; 8 Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/re-ex6-p5</link>
            <description>Question 7 &amp; 8 Review Exercise 6

Solutions of Question 7 &amp; 8 of Review Exercise 6 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$P(A)=0.8, P(B)=0.5$$P(B / A)=0.4$$P(A \cap B)$\begin{align}
P(B \mid A)&amp;=\dfrac{P(A \cap B)}{P(A)} \\
\Rightarrow P(A \cap B)&amp;=P(B \mid A) \cdot P(A)\\
&amp;=0.4 \times 0.8=0.32\end{align}$P(A)=0.8, P(B)=0.5$$P(B / A)=0.4$$P(A …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:01 +0000</pubDate>
        </item>
        <item>
            <title>Question 11 Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit06/re-ex6-p7</link>
            <description>Question 11 Review Exercise 6

Solutions of Question 11 of Review Exercise 6 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$$n(S)=4$$$\dfrac{1}{4}$$$\quad P( orange )=\dfrac{1}{4}$$$\dfrac{1}{4}$$\dfrac{1}{4}$\begin{align}P(\operatorname{Red})&amp;=\dfrac{1}{4}\\
P( Green )&amp;=\dfrac{1}{4}\end{align}$P(R \cap G)=\phi$$R$$G$\begin{align}\boldsymbol{P}( Red o…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:03 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p1</link>
            <description>Question 1 Exercise 7.1

Solutions of Question 1 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$2+4+6+\cdots+2 n=n(n+1)$$n=1$$$2=1(1+1)=2 $$$n=1$$n=k$$$2+4+6+\cdots+2 k=k(k+1)....(i)$$$n=k+1$$(k+1)^{t h}$$$a_{k+1}=\mathbf{2}(k+1)=2 k+2 $$$k+1$\begin{align}2+4+6+\cdots+2 k+2(k+1)&amp; =k(k+1)+2(k+1) \\
&amp; =(k+1)[k+2] \\
&amp; =(k+1)(k+1+1)\end{a…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:07 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p2</link>
            <description>Question 2 Exercise 7.1

Solutions of Question 2 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$1+5+9+\ldots+(4 n-3)=n(2 n-1)$$n=1$$$1=1(2.1-1)=1$$$n=1$$n=k$\begin{align}1+5+9+\ldots+(4 k-3)\\
&amp; =k(2 k-1)....(i) \\
\end{align}$n=k+1$$k+1$$$a_{k-1}=4(k+1)-3=4 k+1 $$$(k+1)^{t h}$\begin{align}1+5+9+\ldots+(4 k-3)+(4 k+1)&amp; =k(2 k-1)+4 k+1 …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:12 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p3</link>
            <description>Question 3 Exercise 7.1

Solutions of Question 3 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$3+6+9+\ldots+3 n=\dfrac{3 n(n+1)}{2}$$n=1$$3=\dfrac{3.1(1+1)}{2}=3$$n=1$$n=k$$$3+6+9+\ldots+3 k=\dfrac{3 k(k+1)}{2}....(i)$$$n=k+1$$(k+1)$$a_{k+1}=3(k+1)$$(k+1)^{t h}$\begin{align}3+6+9+\ldots+3 k+3(k+1) &amp; =\dfrac{3 k(k+1)}{2}+3(k+1) \\
&amp; =3…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:13 +0000</pubDate>
        </item>
        <item>
            <title>Question 4 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p4</link>
            <description>Question 4 Exercise 7.1

Solutions of Question 4 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$3+7+11+\cdots+(4 n-1)=n(2 n+1)$$n=1$$$3=1(2+1)=3 $$$n=1$$n=k$\begin{align}3+7+11+\cdots+(4 k-1) 
&amp; =k(2 k+1)....(i) \end{align}$n=k+1$$(k+1)$$a_{k+1}=4(k+1)-1$$(k+1)^{t h}$\begin{align}
3+7+11+\cdots+(4 k-1)+[4(k+1)-1] &amp; =k(2 k+1)+4(k+1)-1 \…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:13 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p5</link>
            <description>Question 5 Exercise 7.1

Solutions of Question 5 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$1^3+2^3+3^3+\ldots+n^3=\left[\dfrac{n(n+1)}{2}\right]^2$$n=1$$1^3=1=\left[\dfrac{1(1+1)}{2}\right]^2=1$$n=1$$n=k_1$\begin{align}1^3+2^3+3^3+\ldots+k^3&amp; =[\dfrac{k(k+1)}{2}]^2....(i)\end{aligned}
3. Now $$ the $$ term of the given series on l…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:14 +0000</pubDate>
        </item>
        <item>
            <title>Question 6 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p6</link>
            <description>Question 6 Exercise 7.1

Solutions of Question 6 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$1(1 !)+2(2 !)+3(3 !)+\ldots+n(n !)= -(n+1) !-1$$n=1$$$1(1 !)=1=(1+1) !-1=2 !-1=1 $$$n=1$$n=k$\begin{align}1(1 !)+2(2 !)+3(3 !)+\ldots+k(k !)&amp; =(k+1) !-1  \ldots . .(i)\end{align}$n=k+1$$(k+1)^{t h}$$a_{k+1}=(k+1)[(k+1) !]$$a_{k-1}$\begin{ali…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:14 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p7</link>
            <description>Question 7 Exercise 7.1

Solutions of Question 7 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$1.2+2.3+3.4+\ldots+n(n+1)=\dfrac{n(n+1)(n+2)}{3}$$n=1$$$1.2=2=\dfrac{1(1+1)(1+2)}{3}=2 $$$n=1$$n=k$\begin{align}1.2+2.3+3.4+\ldots+k(k+1)&amp; =\dfrac{k(k+1)(k+2)}{3}....(i)\end{align}$n=k+1$$(k-1)^{t h}$$a_{k+1}=(k+1)(k+ 2)$$(k+1)^{\text {th }}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:19 +0000</pubDate>
        </item>
        <item>
            <title>Question 8 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p8</link>
            <description>Question 8 Exercise 7.1

Solutions of Question 8 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$1+2+2^2+2^3+\ldots+2^n 1=2^n-1$$n=1$$1=2^1-1=1$$n=1$$n-k&gt;1$\begin{align}1+2+2^2+2^3+\ldots+2^{k-1} \\
&amp; =2^k-1 ....(i)\end{align}$n-k-1$$(k+1)^{t h}$$a_{k+1}=2^k$$a_{k+1}$\begin{align}1+2+2^2+2^3+\ldots+2^{k-1}-2^k &amp; =2^k-12^k \\
&amp; =2^k+2^k-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:19 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p9</link>
            <description>Question 9 Exercise 7.1

Solutions of Question 9 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\dfrac{1}{3}+\dfrac{1}{9}+\dfrac{1}{27}+\ldots+\dfrac{1}{3^n}=\dfrac{1}{2}[1-\dfrac{1}{3^n}]$$n=1$$$\dfrac{1}{3}-\dfrac{1}{2}[1-\dfrac{1}{3}]-\dfrac{1}{2} \dfrac{2}{3}=\dfrac{1}{3} $$$n=1$$n=k$$$\dfrac{1}{3}+\dfrac{1}{9}+\dfrac{1}{27}+\ldots…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:21 +0000</pubDate>
        </item>
        <item>
            <title>Question 10 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p10</link>
            <description>Question 10 Exercise 7.1

Solutions of Question 10 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\left(\begin{array}{1}5 \\5 \end{array}\right)+\left(\begin{array}{l}6 \\ 5\end{array}\right)+\left(\begin{array}{l}7 \\ 5\end{array}\right)+\ldots+\left(\begin{array}{c}n+4 \\ 5\end{array}\right)=\left(\begin{array}{c}n+5 \\ 6\end{array}\…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:07 +0000</pubDate>
        </item>
        <item>
            <title>Question 11 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p11</link>
            <description>Question 11 Exercise 7.1

Solutions of Question 11 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.\begin{align}
&amp; \left(\begin{array}{l}
2 \\
2
\end{array}\right)+\left(\begin{array}{l}
3 \\
2
\end{array}\right)+\left(\begin{array}{l}
4 \\
2
\end{array}\right)+\ldots+\left(\begin{array}{l}
n \\
2
\end{array}\right)=\left(\begin{array}{c…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:08 +0000</pubDate>
        </item>
        <item>
            <title>Question 12 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p12</link>
            <description>Question 12 Exercise 7.1

Solutions of Question 12 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\dfrac{5^{2 n}-1}{24}$$n=1$$$\dfrac{5^{2 n}-1}{24}=\dfrac{5^{2.1}-1}{24}=\dfrac{24}{24}=1 \in \mathbb{Z}$$$n=1$$n=k&gt;1$$$\dfrac{5^{2 k}-1}{24} \in \mathbb{Z}$$$n=k+1$\begin{align}\dfrac{5^{2(k+1)}-1}{24}&amp;=\dfrac{5^{2 k+2}-1}{24} \\
&amp; =\dfra…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:09 +0000</pubDate>
        </item>
        <item>
            <title>Question 13 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p13</link>
            <description>Question 13 Exercise 7.1

Solutions of Question 13 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$2^n&gt;n \forall n \in \mathbf{N}$$n=1$$2^n=2^1=2$$n=1$$2&gt;1$$n=1$$n=l&gt;I$$2^k&gt;k\cdots(i)$$n=k+1$\begin{align}
&amp; 2^{k+1}=2^k \cdot 2&gt;k \cdot 2 \quad \text { by (i) } \\
&amp; \Rightarrow 2^{k+1}&gt;2 k=k+k \\
&amp;\Rightarrow 2^{k+1}&gt;k+1 \text {. as } k&gt;1…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:10 +0000</pubDate>
        </item>
        <item>
            <title>Question 14 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p14</link>
            <description>Question 14 Exercise 7.1

Solutions of Question 14 of Exercise 7.1 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$5$$3^{2 n-1}+2^{2 n-1}$$n$$n=1$$$3^{2 n-1}+2^{2 n-1}=3^{2.1-1}+2^{2.1-1}=5 \text {. }$$$5$$5$$5$$5.$$n=1$$n=k&gt;1$$54$$3^{2 k} 1+2^{2 k} \quad 1$$$3^{2 k-1}+2^{2 k-1}=5 Q$$$Q$$n=k+1$\begin{align}
3^{2(k+1)-1}+2^{2(k+1)-1} &amp; =3^{2 k+2-1}+2^{2…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:10 +0000</pubDate>
        </item>
        <item>
            <title>Question 15 Exercise 7.1</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-1-p15</link>
            <description>Question 15 Exercise 7.1

Solutions of Question 15 of Exercise 7.1 of Unit 06: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$a+b$$a^n-b^n$$n$$n$$n=2 n, \quad m \in \mathbb{Z}^{+}$$m=1$$$a^{2 n}-b^{2 m}=a^2-b^2=(a+b)(a-b)$$$\Rightarrow(a+b)$$a^2-b^2$$m=1$$n=2$$m=k$$$a^{2 k}-b^{2 k}=Q(a+b)$$$Q$$m=k+1$\begin{align}a^{2(k+1)}-b^{2(k-1)} &amp; =a^{2 k+2}-b^{2 k+2} \\
&amp; =…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:12 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p1</link>
            <description>Question 1 Exercise 7.2

Solutions of Question 1 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$(x^2-\dfrac{1}{y})^4$\begin{align}(x^2-\dfrac{1}{y})^4&amp;=(x^2)^4+{ }^4 C_1(x^2)^3(-\dfrac{1}{y})+ \\
&amp; { }^4 C_2(x^2)^2(-\dfrac{1}{y})^2+{ }^4 C_3(x^2)(-\dfrac{1}{y})^3 + { }^4 C_4(-\dfrac{1}{y})^4 \\
&amp; =x^8- \dfrac{4x^6}{y}+\dfrac{6x^4}{y^2}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:21 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p2</link>
            <description>Question 2 Exercise 7.2

Solutions of Question 2 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$4^{th}$$(2+a)^7$$\ln$$n=7$$a=2$$b=a$$$T_{r+1}=\frac{7 !}{(7-r) ! r !}(2)^{7-r } a^r $$$4^{\text {th }}$$r=3$\begin{align}
&amp; T_{3+1}=\dfrac{7 !}{(7-3) ! 3 !} 2^{7-3} a^3 \\
&amp; \Rightarrow T_4=\dfrac{7 !}{4 ! 3 !} \cdot 2^4 a^3 \\
&amp; \Rightarrow…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:23 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p3</link>
            <description>Question 3 Exercise 7.2

Solutions of Question 3 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$x$$(\dfrac{4 x^2}{3}-\dfrac{3}{2 x})$$n=9, \quad a=\dfrac{4 x^2}{3}$$b=-\dfrac{3}{2 x}$$T_{r+1}$$x$$T_{r+1}$\begin{align}T_{r+1}&amp;=\dfrac{9 !}{(9-r) ! r !}(\dfrac{4 x^2}{3})^{9-r}(-\dfrac{3}{2 x})^r \\
&amp; =\dfrac{9 !}{(9-r) ! r !} \cdot \dfrac…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:24 +0000</pubDate>
        </item>
        <item>
            <title>Question 4 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p4</link>
            <description>Question 4 Exercise 7.2

Solutions of Question 4 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$x^{23}$$(x^2-x)^{20}$$n=20, \quad a=x^2$$b=-x$$T_{r, 1}$$x^{23}$\begin{align}T_{r-1}&amp;=\dfrac{20 !}{(20-r) ! r !}(x^2)^{20 r}(-x)^r \\
&amp; =\dfrac{20 !}{(20-r) ! r !}(-1)^r \cdot x^{40-2 r+r} \\
&amp; =\dfrac{20 !}{(20-r) ! r !}(-1)^r x^{40-r}\end{…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:25 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p5</link>
            <description>Question 5 Exercise 7.2

Solutions of Question 5 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$(\dfrac{a}{x}+b x)^8$$a=\dfrac{a}{x}$$b=b x$$n=8$$n-8$$8+1=9$$$(\dfrac{8+2}{2})^{t h}=5^{t h}$$T_{r+1}$$$T_{r+1}=\dfrac{8 !}{(8-r) ! r !}(\dfrac{a}{x})^{8-r}(b x)^r$$$T_5$$r=4$\begin{align}T_5&amp;=\dfrac{8 !}{(8-4) ! 4 !}(\dfrac{a}{x})^{8-4}(b …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:25 +0000</pubDate>
        </item>
        <item>
            <title>Question 6 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p6</link>
            <description>Question 6 Exercise 7.2

Solutions of Question 6 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$(2 \sqrt{x}-\dfrac{3}{x \sqrt{x}})^{23}$$a=2 \sqrt{x}$$b=-\dfrac{3}{x \sqrt{x}}$$n=23$$x$\begin{align}
T_{r+1}&amp;=\dfrac{23 !}{(23-r) ! r !}(2 \sqrt{x})^{23-r}(-\dfrac{3}{x \sqrt{x}})^r \\
&amp; =\dfrac{23 !}{(23-r) ! r !} \cdot 2^{23-r} \cdot(-3)…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:27 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p7</link>
            <description>Question 7 Exercise 7.2

Solutions of Question 7 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$(2+\sqrt{3})^5+(2-\sqrt{3})^5$\begin{align}(2+\sqrt{3})^5+(2 \cdot \sqrt{3})^5&amp; =[(2)^5+{ }^5 C_1 \cdot 2^4 \cdot \sqrt{3}+{ }^5 C_2 \cdot 2^3 \cdot(\sqrt{3})^2 \\
&amp; +^5 C_3 \cdot 2^2 \cdot(\sqrt{3})^4+{ }^5 C_4 \cdot 2 \cdot(\sqrt{3})^4 \\
…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:27 +0000</pubDate>
        </item>
        <item>
            <title>Question 8 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p8</link>
            <description>Question 8 Exercise 7.2

Solutions of Question 8 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$(3-2 x)^{10}$$x=\frac{3}{4}$$\left(3-2,1^{10}=3^{10}\left(1-\frac{3 x}{2}\right)^{10}\right.$$\left(1-\frac{3 x}{2}\right)^{10}$$p+1$$: 3-\mathbf{2}_1 1^{10}$$T_{5} !=\left(\begin{array}{c}10 \\ 5\end{array}\right) 3^{10} 5-2 \gamma^{15}$$x=…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:28 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p9</link>
            <description>Question 9 Exercise 7.2

Solutions of Question 9 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$(x-y)=&quot;$$x=12$$y-4$$x=12$$$
\begin{aligned}
&amp; \left(x \quad y=20(12-y)^{20}\right. \\
&amp; =12^{2 n}\left(\begin{array}{ll}
1 &amp; \frac{y}{12}
\end{array}\right)^{31}
\end{aligned}
$$$\frac{(n+1) \cdot x}{1+|x|}$$\left(\frac{1}{12}\right)^2 \cdot…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:28 +0000</pubDate>
        </item>
        <item>
            <title>Question 10 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p10</link>
            <description>Question 10 Exercise 7.2

Solutions of Question 10 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$n=2 ;$$s=2^{n-1}$$$
\left.(1+x)^n=\left(\begin{array}{l}
n \\
\vdots
\end{array}\right)+\left(\begin{array}{l}
m \\
1
\end{array}\right) x+\left(\begin{array}{l}
n \\
2
\end{array}\right) x^2-\ldots+i_n^*\right) x^n \cdot
$$$x=1$$(1 \div 1…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:22 +0000</pubDate>
        </item>
        <item>
            <title>Question 11 Exercise 7.2</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-2-p11</link>
            <description>Question 11 Exercise 7.2

Solutions of Question 11 of Exercise 7.2 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$(1+x)^n$$\left(\begin{array}{l}n \\ r\end{array}\right)=\mathrm{C}_r$$\mathrm{C}_1+2 \mathrm{C}_2 x+3 \mathrm{C}_3 x^2+\ldots \ldots . .+\mathrm{nC}_{\mathrm{n}} x^{\mathrm{n}-1}=\mathrm{n}(1+x)^{\mathrm{n}-1}$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:22 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p1</link>
            <description>Question 1 Exercise 7.3

Solutions of Question 1 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\frac{1}{2}$$$
\begin{aligned}
&amp; (1-x)^{\frac{1}{2}}=1+\frac{1}{2} x+ \\
&amp; \frac{\frac{1}{2}\left(-\frac{1}{2}-1\right)}{2 !}(-x)^2
\end{aligned}
$$$$
\begin{aligned}
&amp; +\frac{-\frac{1}{2}\left(-\frac{1}{2}-1\right)\left(-\frac{1}{2}-2\right…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:29 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p2</link>
            <description>Question 2 Exercise 7.3

Solutions of Question 2 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\sqrt{26}$$$
\begin{aligned}
&amp; \sqrt{26}=\sqrt{25+1} \\
&amp; =\sqrt{25} \sqrt{1+\frac{1}{25}}=5\left[1+\frac{1}{25}\right]^{\frac{1}{2}}
\end{aligned}
$$$$
\begin{aligned}
&amp; \sqrt{26}=5\left[1+\frac{1}{25}\right]^{\frac{1}{2}} \\
&amp; =5\left[1+\f…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:32 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p3</link>
            <description>Question 3 Exercise 7.3

Solutions of Question 3 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\sqrt{\frac{1-x}{1+x}}$$x^3$$\sqrt{\frac{1-x}{1+x}}$$$
=(1-x)^{\frac{1}{2}}(1+x)^{-\frac{1}{2}} \text {. }
$$$$
\begin{aligned}
&amp; (1-x)^{\frac{1}{2}}(1+x)^{\frac{1}{2}} \\
&amp; =\left[1-\frac{x}{2}+\frac{\frac{1}{2}\left(\frac{1}{2}-1\right)}{2…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:33 +0000</pubDate>
        </item>
        <item>
            <title>Question 4 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p4</link>
            <description>Question 4 Exercise 7.3

Solutions of Question 4 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$x$$x^2$$x$$$
\sqrt{\frac{1-3 x}{1+4 x}}=1-\frac{7 x}{2}
$$$$
\sqrt{\frac{1-3 x}{1-4 x}}=(1-3 x)^{\frac{1}{2}}(1+4 x)^{-\frac{1}{2}}
$$$x^2$$x$$$
\begin{aligned}
&amp; =\left(1-\frac{3 x}{2}\right) \times\left(1-\frac{4 x}{2}\right) \\
&amp; =\left(1…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:34 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 and 6 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p5</link>
            <description>Question 5 and 6 Exercise 7.3

Solutions of Question 5 and 6 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$x$$x^2$$x$$$
\frac{(8+3 x)^{\frac{2}{3}}}{(2+3 x) \sqrt{4-5 x}}=1-\frac{5 x}{8}
$$$$
\frac{\sqrt[4]{3}-3 x j^{\frac{2}{3}}}{2 \cdot 3 x+4-5 x}
$$$$
\begin{aligned}
&amp; =\frac{8^{\frac{2}{3}}\left(1+\frac{3 x}{8}\right)^{\frac{2}{3}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:34 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 and 8 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p6</link>
            <description>Question 7 and 8 Exercise 7.3

Solutions of Question 7 and 8 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$x^4$$(1-x)^{\frac{1}{4}}+(1-x)^{\frac{1}{4}}=a-b x^2$$a$$b$$$
\begin{aligned}
&amp; (1+x)^{\frac{1}{4}}+(1-x)^{\frac{1}{4}} \\
&amp; =\left[1+\frac{x}{4}+\frac{\frac{1}{4}\left(\frac{1}{4}-1\right)}{2 !} x^2+\right. \\
&amp; \left.\frac{\fra…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:35 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p7</link>
            <description>Question 9 Exercise 7.3

Solutions of Question 9 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$x^{\prime \prime}$$\left(\frac{1+x}{1-x}\right)^2$$$
\begin{aligned}
&amp; \left(\frac{1+x}{1-x}\right)^2=(1+x)^2(1-x)^{-2} \\
&amp; =\left(x^2+2 x+1\right)(1-x)^2
\end{aligned}
$$$$
\begin{aligned}
&amp; =\left(x^2+2 x+1\right)[1+2 x+ \\
&amp; \frac{-2(-2-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:36 +0000</pubDate>
        </item>
        <item>
            <title>Question 10 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p8</link>
            <description>Question 10 Exercise 7.3

Solutions of Question 10 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$1-\frac{1}{2^2}+\frac{1.3}{2 !} \cdot \frac{1}{2^4}+\ldots$$(1+x)^n$$$
\begin{aligned}
&amp; 1+n x+\frac{n(n-1)}{2 !} x^2 \\
&amp; +\frac{n(n-1(n-2))}{3 !} x^3+\ldots
\end{aligned}
$$$n x=-\frac{1}{4}$$\frac{n(n-1)}{2 !} x^2=\frac{1.3}{2 !} \cdot …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:37 +0000</pubDate>
        </item>
        <item>
            <title>Question 11 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p9</link>
            <description>Question 11 Exercise 7.3

Solutions of Question 11 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$y=\frac{1}{2^2}+\frac{1.3}{2 !} \cdot \frac{1}{2^4}+\frac{1 \cdot 3 \cdot 5}{3 !} \cdot \frac{1}{2^6}+\ldots$$y^2+2 y-1=0$$y=\frac{1}{2^2}+\frac{1.3}{2 !} \cdot \frac{1}{2^4}+\frac{1.3 \cdot 5}{3 !} \cdot \frac{1}{2^6}+\ldots$$$
S=y+1=1+\f…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:38 +0000</pubDate>
        </item>
        <item>
            <title>Question 12 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p10</link>
            <description>Question 12 Exercise 7.3

Solutions of Question 12 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$2 y=\frac{1}{2^2}+\frac{1.3}{2 !} \cdot \frac{1}{2^4}+\frac{1.3 \cdot 5}{3 !} \cdot \frac{1}{2^6}+\ldots$$4 y^2+4 y-1=0$$$
2 y=\frac{1}{2^2}+\frac{1.3}{2 !} \cdot \frac{1}{2^4}-\frac{1.3 \cdot 5}{3 !} \cdot \frac{1}{2^6}+\ldots
$$$S=2 y+1=…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:30 +0000</pubDate>
        </item>
        <item>
            <title>Question 13 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p11</link>
            <description>Question 13 Exercise 7.3

Solutions of Question 13 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$x$$x^3$$x$$n^{\text {th }}$$1+x$$\frac{2 n+(n+1) x}{2 n+(n-1) x}$$$
\begin{aligned}
&amp; (1+x)^{\frac{1}{n}}=\frac{2 n+(n+1) x}{2 n+(n-1) x} \\
&amp; \frac{2 n+(n+1) x}{2 n+(n-1) x} \\
&amp; =1+\frac{1}{n} x+\frac{\frac{1}{n}\left(\frac{1}{n}-1\right…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:31 +0000</pubDate>
        </item>
        <item>
            <title>Question 14 Exercise 7.3</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/ex7-3-p12</link>
            <description>Question 14 Exercise 7.3

Solutions of Question 14 of Exercise 7.3 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$x$$p x^p-q x^q=(p-q) x^{p+q}$$x$$x=1+h$$h \longrightarrow 0$$$
p x^p-q x^q=p(1+h)^p-q(1+h)^q
$$$$
\begin{aligned}
&amp; p x^p-q x^q \\
&amp; =p(1+p h+\text { higher powers h) } \\
&amp; -q(1+q h+\text { higher powcrs } h) \\
&amp; \Rightarrow p x^p-q x^q=…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:31 +0000</pubDate>
        </item>
        <item>
            <title>Question 1 Review Exercise 7</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/re-ex7-p1</link>
            <description>Question 1 Review Exercise 7

Solutions of Question 1 of Review Exercise 7 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.
Chose the correct option.$O, P, Q, R, S, T, U$$2520$$9040$$5140$$4880$$2520$$\{1,2,3,4,5,6,7\}$$14$$42$$28$$21$$28$$\{1,2,3,4,6,7,8\}$$3$$7$$120$$180$$144$$96$$120$$\dfrac{(n+2) !(n-2) !}{(n+1) !(n-1) !}$$(n-3)$$(\dot{n}-1)$$\dfrac…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:38 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 Review Exercise 7</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/re-ex7-p2</link>
            <description>Question 2 Review Exercise 7

Solutions of Question 2 of Review Exercise 7 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\left(2 x^3+3 y\right)^8$$a=2 x^3$$b=3 y$$n=8$$n=8$$\frac{8+2}{2}=5$$$
\begin{aligned}
&amp; T_5=\frac{8 !}{(8-4) ! 4 !}\left(2 x^3\right)^{8-4}(3 y)^4 \\
&amp; T_5=70.2^4 \cdot 3^4 \cdot x^{12} \cdot y^4 \\
&amp; =90720 x^{12} y^4
\end{aligne…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:40 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 &amp; 4 Review Exercise 7</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/re-ex7-p3</link>
            <description>Question 3 &amp; 4 Review Exercise 7

Solutions of Question 3 &amp; 4 of Review Exercise 7 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$(2 x-4 y)^7$$n=7, a=2 x$$b=-4 y$$$
\begin{aligned}
&amp; T_{3+1}=\frac{7 !}{(7-3) ! 3 !}(2 x)^{7 \cdot 3}(-4 y)^3 \\
&amp; =\frac{7 !}{(7-3) ! 3 !} \cdot\left(2^4\right) \cdot(-4)^3 \cdot x^4 y^3 \\
&amp; \Rightarrow T_4=-35840 x^4 y^3…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:40 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 &amp; 6 Review Exercise 7</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/re-ex7-p4</link>
            <description>Question 5 &amp; 6 Review Exercise 7

Solutions of Question 5 &amp; 6 of Review Exercise 7 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$\left(\frac{2}{x^2}+\frac{x^2}{2}\right)^{10}$$n=10, a^{\prime}=\frac{2}{x^2}$$b=\frac{x^2}{2}$$T_{r+1}$$x$$$
\begin{aligned}
&amp; T_{r+1}=\frac{10 !}{(10-r) ! r !}\left(\frac{2}{x^2}\right)^{10 r}\left(\frac{x^2}{2}\right)^r …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:41 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 &amp; 8 Review Exercise 7</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/re-ex7-p5</link>
            <description>Question 7 &amp; 8 Review Exercise 7

Solutions of Question 7 &amp; 8 of Review Exercise 7 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.$7^n-3^n$$n=1$$7^k-3^k=7-4=4$$n=1$$n=k&gt;1$$7^n-3^n=4 Q$$Q$$n=k+1$$$
\begin{aligned}
&amp; 7^{k+1}-3^{k+1}=7.7^k-3.3^k \\
&amp; =(4+3) \cdot 7^k-3.3^k \\
&amp; =4.7^k+3.7^k-3.3^k
\end{aligned}
$$$$
\begin{aligned}
&amp; =4.7^k+3\left[7^k-3^k\…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:41 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 and 10 Review Exercise 7</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/re-ex7-p6</link>
            <description>Question 9 and 10 Review Exercise 7

Solutions of Question 9 and 10 of Review Exercise 7 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:43 +0000</pubDate>
        </item>
        <item>
            <title>Question 11 Review Exercise 7</title>
            <link>https://www.mathcity.org/math-11-kpk/sol/unit07/re-ex7-p7</link>
            <description>Question 11 Review Exercise 7

Solutions of Question 11 of Review Exercise 7 of Unit 07: Permutation, Combination and Probablity. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Thu, 01 Feb 2024 02:36:43 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-1-p1</link>
            <description>Question 1, Exercise 6.1

Solutions of Question 1 of Exercise 6.1 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $10!$\begin{align*} 
10! &amp;= 10 \times 9 \times 8 \times 7 \times 6 \times 5 \times 4 \\
&amp;= 3628800
\end{align*}$\dfrac{12!}{7! 3! 2!}$\begin{align*}
\dfrac{12!}{7! \, 3! \, 2!} &amp;= \dfrac{12 \times 11 \times 10 \times 9 \times 8 \times 7!}{7! …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:29 +0000</pubDate>
        </item>
        <item>
            <title>Question 2, Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-1-p2</link>
            <description>Question 2, Exercise 6.1

Solutions of Question 2 of Exercise 6.1 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\quad 14\cdot 13\cdot 12\cdot 11$\begin{align*}
&amp;14\cdot 13\cdot 12\cdot 11\\
= &amp; \dfrac{14\cdot 13\cdot 12\cdot 11\cdot 10!}{10!} \\
= &amp; \dfrac{14!}{10!} 
\end{align*}$\quad 1\cdot 3\cdot 5 \cdot 7 \cdot 9$$$1 \times 3\times 5\times 7 \time…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:29 +0000</pubDate>
        </item>
        <item>
            <title>Question 3 and 4, Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-1-p3</link>
            <description>Question 3 and 4, Exercise 6.1

Solutions of Question 3 and 4 of Exercise 6.1 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $\quad \dfrac{1}{5!}+\dfrac{3}{6!}+\dfrac{1}{7!}=\dfrac{4}{315}$\begin{align*}
LHS = &amp; \dfrac{1}{5!}+\dfrac{3}{6!}+\dfrac{1}{7!} \\
= &amp; \dfrac{1}{5!}+\dfrac{3}{6\cdot 5!}+\dfrac{1}{7\cdot 6\cdot 5!}\\
= &amp; \dfrac{1}{5!}\left(1+\dfr…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:31 +0000</pubDate>
        </item>
        <item>
            <title>Question 5, Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-1-p4</link>
            <description>Question 5, Exercise 6.1

Solutions of Question 5 of Exercise 6.1 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n$$\quad \dfrac{n}{(n-4)!}=\dfrac{3.3!}{(n-3)!}$\begin{align*}
\dfrac{n}{(n-4)!}&amp;=\dfrac{3.3!}{(n-3)!}\\
\dfrac{n}{(n-4)!}&amp;=\dfrac{3.3!}{(n-3)(n-4)!}\\
n&amp;=\dfrac{3\times 6}{n-3}\\
n(n-3)&amp;=18\\
n^2-3n&amp;=18\\
n^2-2n-18&amp;=0\\
n^2+3n-6n-18&amp;=0\\
n(…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:34 +0000</pubDate>
        </item>
        <item>
            <title>Question 6(i-v), Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-1-p5</link>
            <description>Question 6(i-v), Exercise 6.1

Solutions of Question 6(i-v) of Exercise 6.1 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n\in N$$\quad (2n)!=2^n(n!)[1\cdot3\cdot5 \cdots (2n-1)]$\begin{align*}
(2n)!&amp;= (2n)(2n-1)(2n-2)(2n-3)\cdots (2n-n)(2n-(n+1))\cdots4.3.2.1\\
&amp;= (2n)(2n-1)(2n-2)(2n-3)\cdots (n)(n-1)\cdots4.3.2.1\\
&amp;= (2n)(2n-1)(2n-2)(2n-3)\cdots (n…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:32 +0000</pubDate>
        </item>
        <item>
            <title>Question 6(vi-ix), Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-1-p6</link>
            <description>Question 6(vi-ix), Exercise 6.1

Solutions of Question 6(vi-ix) of Exercise 6.1 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n\in N$$\quad 33!$$2^{15}$$$33!=33.32.31\cdots4.3.2.1$$$2,4,8,16,32$$2^1,2^2,2^3,2^4,2^5$\begin{align*}33!&amp;=2^5.2^4.2^3.2^2.2(33\times31\times\cdots6\times5\times3\times1)\\
&amp;=2^{15}(33\times31\times\cdots\times3\times1)\end{al…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:34 +0000</pubDate>
        </item>
        <item>
            <title>Question 7(i-vi), Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-1-p7</link>
            <description>Question 7(i-vi), Exercise 6.1

Solutions of Question 7(i-vi) of Exercise 6.1 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n$$\quad \dfrac{n!}{(n-2)!}=930,\quad n \geq 2$\begin{align*}
\dfrac{n!}{(n-2)!}&amp;=930\\
\dfrac{n(n-1)(n-2)!}{(n-2)!}&amp;=930\\
n(n-1)&amp;=930\\
n^2-n-930&amp;=0
\end{align*}\begin{align*}
n&amp;=\dfrac{1\pm \sqrt{1+4(930)}}{2}\\
&amp;=\dfrac{1\pm …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:37 +0000</pubDate>
        </item>
        <item>
            <title>Question 7(vii-xi), Exercise 6.1</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-1-p8</link>
            <description>Question 7(vii-xi), Exercise 6.1

Solutions of Question 7(vii-xi) of Exercise 6.1 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n$$\quad n!=990 \cdot (n-3)!$\begin{align*}
n!&amp;=990  (n-3)!\\
n(n-1)(n-1)(n-3)!&amp;=990  (n-3)!\\
n(n-1)(n-1)&amp;=990 \\
n^3-3n^2+2n-990 &amp;=0\\
\end{align*}\[\begin{array}{c|cccc}
 &amp; 1 &amp; -3 &amp; 2 &amp; -990 \\  
11 &amp; 0  &amp; 11 &amp; 88 &amp; 990 \\…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:36 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p1</link>
            <description>Question 1, Exercise 6.2

Solutions of Question 1 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n \in N$$\quad^nP_r=\dfrac{n!}{(n-r)!}$$n$$r$$\dot{n}$$2^{\text {nd }}$$(n-1)$$3^{\text {rd }}$$(n-2)$$r^{\text {th }}$$(n-(r-1)$$$
{ }^{n} P_{r}=n(n-1)(n-2) \ldots(n-(r-1))
$$$(n-r)(n-r-1) \ldots 3,2.1$${ }^{n} P_{r}=\frac{n(n-1)(n-2)\ldots…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:40 +0000</pubDate>
        </item>
        <item>
            <title>Question 2, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p2</link>
            <description>Question 2, Exercise 6.2

Solutions of Question 2 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n$$\quad ^nP_4=20\, ^nP_2$\begin{align*}
\dfrac{m}{(n-4)!}&amp;=20 \cdot \dfrac{m}{(n-2)!}\\
\dfrac{1}{(n-4)!}&amp;=\dfrac{20}{(n-2)(n-3)(n-4)!}\\
(n-2)(n-3)&amp;=20\\
n^{2}-5 n+6&amp;=20\\
n^{2}-5 n-14&amp;=0\\
n^{2}+2 n-7 n-14&amp;=0\\
n(n+2)-7(n+2)&amp;=0\\
(n+2)(n-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:49 +0000</pubDate>
        </item>
        <item>
            <title>Question 3, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p3</link>
            <description>Question 3, Exercise 6.2

Solutions of Question 3 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $r$$^6P_{r-1}=^5P_4$\begin{align*}{ }^{6} P_{r-1}&amp;={ }^{5} P_{4}\\
\dfrac{6!}{(6-(r-1))!}&amp;=\dfrac{5!}{(5-4)!}\\
\dfrac{6!}{(7-r)!}&amp;=\dfrac{5!}{1!} \\
\frac{6 \times 5!}{(7-r)!}=\dfrac{5!}{1}
6&amp;=(7-r)!\\
3!&amp;=(7-r)!\\
3&amp;=7-r \\
r&amp;=7-3\\
r&amp;=4\en…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:50 +0000</pubDate>
        </item>
        <item>
            <title>Question 4 and 5, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p4</link>
            <description>Question 4 and 5, Exercise 6.2

Solutions of Question 4 and 5 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $3$$1,2,3,4,5,6,$$3$$6$$\mathrm{I}:$$2$$$\underline{ },\underline{ },\underline{2}$$$={ }^{5} P_{2}=20$$4$$$\underline{ },\underline{ },\underline{4}$$$={ }^{5} P_{2}=20$$6$$$\underline{ },\underline{ },\underline{6}$$$={ }^{5} P_…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:51 +0000</pubDate>
        </item>
        <item>
            <title>Question 6 and 7, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p5</link>
            <description>Question 6 and 7, Exercise 6.2

Solutions of Question 6 and 7 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $4$$$1,2,3,4,5,6$$6$$6$$6$$6$$$\text{Total possibilities }6 \times 6 \times 6 \times 6=6^4=1296$$$1,1,2,2,3,3,4$$=7$$2^{\text {nd }}$$6^{\text {th }}$$1^{\text {st }}, 3^{\text {rd }}, 5^{\text {th }}$$7^{\text {th }}$$2,2,4$$1,1,…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:54 +0000</pubDate>
        </item>
        <item>
            <title>Question 8 and 9, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p6</link>
            <description>Question 8 and 9, Exercise 6.2

Solutions of Question 8 and 9 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $4$$5$$5$$4$$41$$=41 \times 41=576$$2$$3$$4$$$\text{Total flags} =9$$$$\text{Repetition of blue }=2$$$$\text{Repetition of yellow}=3$$$$\text{Repetition of green}=4$$\begin{align*}\text{Total signals }&amp;=\dfrac{9!}{2!3!4!}\\
&amp;=\dfr…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:54 +0000</pubDate>
        </item>
        <item>
            <title>Question 12 and 13, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p8</link>
            <description>Question 12 and 13, Exercise 6.2

Solutions of Question 12 and 13 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $=5$$5$$=5!=120$$O$$E$$21=2$$3$$3!= 6$$O$$E$$=6 \times 2=12$$0$$E$$=120-12=108$$=7$$7$$=71=5040$$3$$A, I$$E$$3$$4$$$5!=120$$$3$$=6$$$6 \times 120=\mathbf{7 2 0}$$$5040$$720$$3$$5040-720=4320$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:55 +0000</pubDate>
        </item>
        <item>
            <title>Question 14 and 15, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p9</link>
            <description>Question 14 and 15, Exercise 6.2

Solutions of Question 14 and 15 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $3$$=7$$=3$$={ }^{7} P_{3}=\dfrac{7!}{4!}=210$$5$$3$$2$$3$$=31=6$$=(5!\times 3!\times 2!) \times 31=8640$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:57 +0000</pubDate>
        </item>
        <item>
            <title>Question 16 and 17, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p10</link>
            <description>Question 16 and 17, Exercise 6.2

Solutions of Question 16 and 17 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $1,2,3,4,5,6$$1, 3$$5$$=3 \times{ }^{5} P_{5}=360$$4$$1,2,3,4$$5$$1$$={ }^{4} P_{3}=24$$3$$24$$5$$24$$24+24+24=72$$4$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:43 +0000</pubDate>
        </item>
        <item>
            <title>Question 18 and 19, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p11</link>
            <description>Question 18 and 19, Exercise 6.2

Solutions of Question 18 and 19 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $10,000$$0,2,3,5,6$$4$$10000$$3$$5$$0$$3={ }^{3} P=6$$0$$5=3 p_{6}=6$$10000$$5$$=6+6=12$$3$$4$$5$$={ }^{4} P_{3}=2$$4$$5$$4$$5={ }^{4} P_{3}=24$$3$$3$$3$$5=$${ }^{4} P_{2}=12$$3$$5$$3$$5=$${ }^{4} P_{2}=12$$2$$3$$2$$5={ }^{4} …</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:48 +0000</pubDate>
        </item>
        <item>
            <title>Question 20 and 21, Exercise 6.2</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-2-p12</link>
            <description>Question 20 and 21, Exercise 6.2

Solutions of Question 20 and 21 of Exercise 6.2 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $6$$6$$5!$$6$$6!$$=5! \times 6!=86400$$= n = 4$$= {}^4P_4 = 24.$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 08:59:45 +0000</pubDate>
        </item>
        <item>
            <title>Question 1(i-v), Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p1</link>
            <description>Question 1(i-v), Exercise 6.3

Solutions of Question 1(i-v) of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n\in N$$\quad^nC_r=\dfrac{n!}{r!(n-r)!}$$n$$r$$0&lt;r&lt;n$$X$$r$$r$$r$$$
\begin{array}{ll} 
&amp; r!X={ }^{n} P_{r} \\
\Rightarrow &amp; r!X=\frac{n!}{(n-r)!} \\
\Rightarrow &amp; X=\frac{n!}{r!(n-r)!}={ }^{n}{C}_{r}
\end{array}
$$$n\in N$$n\cdot^{…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:24 +0000</pubDate>
        </item>
        <item>
            <title>Question 1(vi-x), Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p2</link>
            <description>Question 1(vi-x), Exercise 6.3

Solutions of Question 1(vi-x) of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n\in N$$\quad^{2n}C_n=\dfrac{2^n[1.3.5.\cdots(2n-1)]}{n!}$\begin{align*}L.H.S &amp;=\quad^{2n}C_n \\
&amp;=\dfrac{(2 n)!}{n!(2 n-n)!}\\
&amp;=\dfrac{(2 n)(2 n-1)(2 n-2)(2 n-n)(2 n-(n+1)) ..2 .1}{n!\cdot n!}\\
&amp;=\dfrac{(2 n)(2 n-1)(2 n-2) ..(…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:26 +0000</pubDate>
        </item>
        <item>
            <title>Question 2, Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p3</link>
            <description>Question 2, Exercise 6.3

Solutions of Question 2 of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n$$\,\, ^nC_5=\,\, ^nC_8$\begin{align*}\dfrac{n!}{5!(n-5)!}=\dfrac{n!}{8!(n-8)!}&amp;\\
\dfrac{1}{8!(n-5)(n-6)(n-7)(n-8)!}&amp;\\
=\dfrac{1}{8 \times 7 \times 6 \times 8!(n-8)!}&amp;\\
336=(n-5)(n-6)(n-7)&amp;\\
(n-5)\left(n^{2}-13 n+42\right)&amp;=336\\
n^{3}-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:26 +0000</pubDate>
        </item>
        <item>
            <title>Question 3, Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p4</link>
            <description>Question 3, Exercise 6.3

Solutions of Question 3 of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $r$$\quad^{15}C_{3r}= ^{15}C_{3+r}$$${ }^{n} C_{r}={ }^{n} C_{n-r}$$\begin{align*}n=15\quad&amp;\text{put} \quad r=3 r\\
n-3 r&amp;=r+3\\
15-3 r&amp;=r+3 \\
15-3 &amp; =3 r+r \\
12 &amp; =4 r\\
r&amp;=3\end{align*}$r$$\quad^{8}C_{r}-\,^7C_3= ^{7}C_{2}$\begin{align*}…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:27 +0000</pubDate>
        </item>
        <item>
            <title>Question 4, Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p5</link>
            <description>Question 4, Exercise 6.3

Solutions of Question 4 of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n$$r$$\,\,^nC_{r-1}:\,^nC_{r}:\,^nC_{r+1}=6:14:21$\begin{align*}\dfrac{n!}{(r-1)!(n-(r-1))!}&amp;: \dfrac{n!}{r!(n-r)!}\\
: \dfrac{n!}{(r+1)!(n-(r+1))!} &amp;= 6:14:21\\
\dfrac{1}{(r-1)!(n-r+1)!}: \dfrac{1}{r!(n-r)!}&amp;\\
: \dfrac{1}{(r+1)!(n-r-1)!}&amp;=…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:27 +0000</pubDate>
        </item>
        <item>
            <title>Question 5 and 6, Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p6</link>
            <description>Question 5 and 6, Exercise 6.3

Solutions of Question 5 and 6 of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $11$$16$$11$$16$${ }^{16} C_{11}$$4368$$11$$11$$16$$10$$15$$$
{ }^{15} C_{10}=3003
$$$5$$3$$3$$1$${ }^{5} C_{1}$$2$${ }^{3} C_{2}$$={ }^{5} C_{1} \times{ }^{3} C_{2}=5 \times 3=15$$2$$={ }^{5} C_{2} \times{ }^{3} C_{1}=10 \times 3…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:29 +0000</pubDate>
        </item>
        <item>
            <title>Question 7 and 8, Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p7</link>
            <description>Question 7 and 8, Exercise 6.3

Solutions of Question 7 and 8 of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $5$$6$$4$$2$$2$$3$$={ }^{4} C_{2} \times{ }^{6} C_{3}=6 \times 20=120$$5$$6$$4$$2$$2$$2$$2,3$$2$$120$$3$$2$$={ }^{4} C_{3} \cdot{ }^{6} C_{2}=4 \times 15=60$$4$$={ }^{4} C_{4} \times{ }^{6} C_{1}=1 \times 6=6$$=120+60+6=186$$5$$6$…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:29 +0000</pubDate>
        </item>
        <item>
            <title>Question 9 and 10, Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p8</link>
            <description>Question 9 and 10, Exercise 6.3

Solutions of Question 9 and 10 of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n$$n$$n$$n$$C_{2}$$n$$n$$={ }^{n} C_{2}-n$$=\frac{n!}{2!(n-2)!}-n$$10$$10$$3$$7$$10$${ }^{10} C_{7}$$7$$3$$7={ }^{10} C_{7}=120$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:33 +0000</pubDate>
        </item>
        <item>
            <title>Question 11 and 12, Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p9</link>
            <description>Question 11 and 12, Exercise 6.3

Solutions of Question 11 and 12 of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $n$$35$$n$\begin{align*}{ }^{n} C_{2}-n&amp;=35\\
\text{or} \quad \dfrac{n!}{2!(n-2)!}-n&amp;=35\\
\dfrac{n(n-1)(n-2)!}{2(n-2)!}-n&amp;=35\\
\dfrac{n(n-1)-2 n}{2}&amp;=35\\
n^{2}-n-2 n&amp;=70\\
n^{2}-3 n-70&amp;=0\\
n^{2}+7 n-10 n-70 &amp; =0 \\
n(n+7)-…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:31 +0000</pubDate>
        </item>
        <item>
            <title>Question 13 and 14, Exercise 6.3</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/ex6-3-p10</link>
            <description>Question 13 and 14, Exercise 6.3

Solutions of Question 13 and 14 of Exercise 6.3 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $6$$1$$1$$2$$6$$1$$6={ }^{6} C_{1}=6$$2$$6={ }^{6} C_{2}=15$$3$$6={ }^{6} C_{3}=20$$4$$6={ }^{6} C_{4}=15$$5$$6={ }^{6} C_{5}=6$$6$$6={ }^{6} C_{6}=1$$$\text{Total}\quad =6+15+20+15+6+1=63$$$A$$B$$C$$8$$5$$A$$3$$B$$C$$5$$8$$A$…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:22 +0000</pubDate>
        </item>
        <item>
            <title>Question 1, Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/re-ex6-p1</link>
            <description>Question 1, Review Exercise 6

Solutions of Question 1 of Review Exercise 6 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $3\,\,^nP_3=^nP_4$$n$$5$$6$$7$$8$$6$$ 480$$600$$720$$840$$720$$r$$r!$$(r+1)!$$r!+1$$ 2r!$$r!$$6$$\dfrac{5}{2}\,\,6!$$6!$$\dfrac{1}{2}\,\,6!$$\dfrac{3}{2}\,\,6!$$\dfrac{5}{2}\,\,6!$$A=\{1,2,3,4,...,20\}. $$3$$5$$7$$8$$8$$A=\{1,3,5,7,…</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:36 +0000</pubDate>
        </item>
        <item>
            <title>Question 2 and 3, Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/re-ex6-p2</link>
            <description>Question 2 and 3, Review Exercise 6

Solutions of Question 2 and 3 of Review Exercise 6 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $4$$26$$$^{26}P_4=358800$$$3$$0$$3$$100&#039;s$$9$$3$$$=10\times 10\times10=1000$$$0$$10$$3-$$0$$$=10\times 10=100$$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:43 +0000</pubDate>
        </item>
        <item>
            <title>Question 4, 5 and 6, Review Exercise 6</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/re-ex6-p3</link>
            <description>Question 4, 5 and 6, Review Exercise 6

Solutions of Question 4, 5 and 6 of Review Exercise 6 of Unit 06: Permutation and Combination. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. $0,2,3,4,5,7$$6$$$=6!=720$$$0$$5$$$5!=120$$$6-$$$=720-120=600$$$7$$$(7-1)!=720$$$2$$$\dfrac{720}{2}=360$$$11!$$10!$$$=11!-10!=36288000$$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:38 +0000</pubDate>
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    </channel>
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