Question

Five boys and seven girls in a history class will go on a field trip during the Easter vacation. They make a committee of three members to prepare for the trip. What is the probability that this committee will consist of three boys? What is the probability that the committee will have two boys and one girl?

Answer 1

number of committes without restriction
= C(12,3) =220

number of committess with three boys
= C(5,3) = 10
prob( 3boys) = 10/220 = 1/22

number of committees with 2 boys, 1 girs
= C(5,2) x C(7,1)
= 70

prob (2boys, 1 girl ) = 70/220 = 7/22