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A singing choir of 4 children is to be formed. The selection pool consists of 8 siblings pairs. In how many ways can a

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by Vincen » Tue Aug 17, 2021 7:25 am

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Answers

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C

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E

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Difficulty—

A singing choir of 4 children is to be formed. The selection pool consists of 8 siblings pairs. In how many ways can a choir be formed if both siblings cannot be selected together?

(A) 360
(B) 720
(C) 1120
(D) 2400
(E) 26880

Answer: C

Source: e-GMAT
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Re: A singing choir of 4 children is to be formed. The selection pool consists of 8 siblings pairs. In how many ways can

by regor60 » Tue Aug 17, 2021 8:36 am
Each child must be from a different sibling pair, so pick 4 sibling pairs from 8:

8!/4!*4! = 70

Since you can pick either child from each sibling pair, there are 2*2*2*2=16 ways to do this.

16*70=C, 1120
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