Latest general Aptitude Question SOLUTION: There are 20 people in your applicant pool, including 5 pairs of identical twins. If you hire 5 people randomly, what are the chances you will hire at least 1 pair of identical tw

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(#M40000179) GENERAL question Keep an EYE

There are 20 people in your applicant pool, including 5 pairs of identical twins.
If you hire 5 people randomly, what are the chances you will hire at least 1 pair of identical twins? (Needless to say, this could cause trouble

Asked In general Naveen (13 years ago)

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dhiresh  (13 years ago)

TOTAL sample space =20C5
for at least one pair of twins let take one pair of twins (5 twins so for this u have 5 ways)and choose the 3 peple from rest of them (way for choosing 3 from 18=18C3) so no of ways for right event=
no of instance of events=5*18C3
so probability(chance) for occuring event=5*18C3/20C5=(5*(18*17*16*15!)/3!*15!)/((20*19*18*17*16*15!)/5!*15!)=5/19
so answer is 5/19

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Rakesh Kumar Kohli  (12 years ago)

In 5 select people if one pair is identical twin then three persons will be selected from remaining 10 people. for which Probability = (1/5)*(3/10)= 3/50

In 5 selected people if two pairs are identical twins then one person will be selected from remaining 10 people. for which Probability = (2/5)*(1/10)= 2/50

Therefore chances that 5 selected people includes at least one pair of identical twins = (3/50) + (2/50) = 5/50 = 1/10 i.e 10% chances.

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