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Probability

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Probability

by sparkle6 » Tue Sep 27, 2011 6:22 am
If a jury of 12 people is to be selected randomly from a pool of 15 potential jurors, and the jury pool consists of 2/3 men and 1/3 women, what is the probability that the jury will comprise of at least 2/3 men?

a. 24/91
b. 45/91
c. 2/3
d. 67/91
e. 84/91

[spoiler]Answer: D. Does anyone know how to solve this using combinations? [/spoiler]
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by user123321 » Tue Sep 27, 2011 7:31 am
we have 10M,5W to form a group of 12 members with atleast 8M(=>8M,4W or 9M,3W or 10M,2W)
so combinations are
10C8*5c4+10C9*5C3+10C10*5C4 = 335

total possible combinations are = 15C12 = 5*7*13

so probability = 335/(5*7*13) = 67/91

user123321
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