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        <title>MathCity.org</title>
        <description>Merging man &amp; maths</description>
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            <title>MathCity.org</title>
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        <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>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 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 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 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 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 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>
        </item>
        <item>
            <title>Review Exercise (Solutions)</title>
            <link>https://www.mathcity.org/math-11-nbf/sol/unit06/rev-ex</link>
            <description>Review Exercise (Solutions)

The solutions of the Review Exercise 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. 

Question 1.$4$$3$$0$$6$$0,2,3,4,5,7$$7$</description>
            <author>anonymous@undisclosed.example.com (Anonymous)</author>
            <pubDate>Sat, 08 Mar 2025 09:00:41 +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 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>
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