Ex 6.4, 1 - Chapter 6 Class 11 Permutations and Combinations

Last updated at August 2, 2026 by

Ex 6.4, 1 - If nC8 = nC2, find nC2 - Binomials Class 11 - Ex 6.4 - Ex 6.4

part 2 - Ex 6.4, 1 - Ex 6.4 - Serial order wise - Chapter 6 Class 11 Permutations and Combinations

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Ex 6.4, 1 If nC8 = nC2, find nC2 . Given nC8 = nC2 If nCr = nCp then either r = p or r = n ā€“ p Thus, nC8 = nC2 8 = n ā€“ 2 8 + 2 = n 10 = n n = 10 Calculating nC2 Putting n = 10 10C2 = 10!/2!(10 āˆ’ 2)! = šŸšŸŽ!/(šŸ! šŸ–!) = (10 Ɨ 9 Ɨ 8!)/((2 Ɨ 1)Ɨ 8!) = (10 Ɨ 9)/2 = 45

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