If there is an equal probability of a child being born a boy or a girl, what is the probability that a couple who have 3 children have two children of the same sex and one of the opposite sex? Pick:
A) 1/3	B) 2/3	C) 1/4	D) 3/4	E) 3/5
Let boy be represented by B and girl by G.   The possible outcomes of two children of same sex and one of opposite sex can be:   BBG OR GBB OR BGB OR GGB OR BGG OR GBG   (1/2*1/2*1/2) + (1/2*1/2*1/2) + (1/2*1/2*1/2) + (1/2*1/2*1/2) + (1/2*1/2*1/2) + (1/2*1/2*1/2)   1/8 + 1/8 + 1/8 + 1/8 + 1/8 + 1/8 = 6/8 = 3/4   ANSWER:(3/4)
<result>D</result>
If there is an equal probability of a child being born a boy or a girl, what is the probability that a couple who have 3 children have two children of the same sex and one of the opposite sex?