Determine n if ^2nC3: ^nC3 = 9:1.(a) 7(b) 14(c) 28(d) 32I have been asked this question in a job interview.I'm obligated to ask this question of Combinations topic in portion Permutations and Combinations of Mathematics – Class 11

Determine n if ^2nC3: ^nC3 = 9:1.(a) 7(b) 14(c) 28(d) 32I have been as

1.	Determine n if ^2nC3: ^nC3 = 9:1.(a) 7(b) 14(c) 28(d) 32I have been asked this question in a job interview.I'm obligated to ask this question of Combinations topic in portion Permutations and Combinations of Mathematics – Class 11
Answer» Correct answer is (b) 14 The BEST I can explain: We know, ^nCr = \(\frac{N!}{(n-r)! r!}\). ^2nC3 / ^nC3 = \(\frac{\frac{n!}{3! (2N-3)!}}{\frac{n!}{3! (n-3)!}}\) = \(\frac{2n! (n-3)!}{n! (2n-3)!}\) 9/1 = \(\frac{2n(2n-1)(2n-2)}{n(n-1)(n-2)}\) 9 = \(\frac{2(2n-1)2}{(n-2)}\) 9n-18 = 8n-4 =>n=14.

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Determine n if ^2nC3: ^nC3 = 9:1.(a) 7(b) 14(c) 28(d) 32I have been asked this question in a job interview.I'm obligated to ask this question of Combinations topic in portion Permutations and Combinations of Mathematics – Class 11

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