Ex 6.4, 1 - Chapter 6 Class 11 Permutations and Combinations
Last updated at Dec. 16, 2024 by Teachoo
Last updated at Dec. 16, 2024 by Teachoo
Ex 6.4, 1 If nC8 = nC2, find nC2 . Given nC8 = nC2 If nCr = nCp then either r = p or r = n โ p Thus, nC8 = nC2 8 = n โ 2 8 + 2 = n 10 = n n = 10 Calculating nC2 Putting n = 10 10C2 = 10!/2!(10 โ 2)! = ๐๐!/(๐! ๐!) = (10 ร 9 ร 8!)/((2 ร 1)ร 8!) = (10 ร 9)/2 = 45
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