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Ex 7.4
Last updated at March 22, 2023 by Teachoo
Ex 7.4, 1 If nC8 = nC2, find nC2 . Given nC8 = nC2 If nCr = nCp then either r = p or r = n β p Thus, nC8 = nC2 8 = n β 2 8 + 2 = n 10 = n n = 10 Calculating nC2 Putting n = 10 10C2 = 10!/2!(10 β 2)! = ππ!/(π! π!) = (10 Γ 9 Γ 8!)/((2 Γ 1)Γ 8!) = (10 Γ 9)/2 = 45