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Permutation and Combination – Class XI – Exercise 7.4

  If nC8 = nC2. find nC2 Solution: We know that, nCa = nCb then a = b or n = a + b Therefore, nC8 = nC2, since 8≠2 , we have 8 + 2 = 10 nC2 = 10C2 = 10!/2!(10-2)! = 10!/2!8! = 10x9x8/2x1x8 = 45 Determine n if (i) (2nC3 :… Continue reading Permutation and Combination – Class XI – Exercise 7.4