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Out of a group of 5 persons, find the number of ways of selecting 3 persons.(a) 1(b) 5(c) 10(d) 15I got this question in unit test.This interesting question is from Combinations in division Permutations and Combinations of Mathematics – Class 11

Answer»

Correct ANSWER is (c) 10

Explanation: Out of a group of 5 persons, we have to select 3 persons. This can be done in ^5C3 ways.

^nCr = \(\frac{n!}{(n-R)! r!}\)

^5C3 = \(\frac{5!}{(5-3)! 3!} = \frac{5*4*3!}{(2)! 3!} = \frac{20}{2}\)

i.e. 10 ways.



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