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 4 children have two children of the same sex and one of the opposite sex?
Select.
A) 1/3 B) 2/3 C) 1/4 D) 1/2 E) 3/5
No of ways of selecting a gender - 2C1   No of ways of selecting any 2 children out of 4 = 4C2   Total possible outcomes - 2^4 (each child can be either a girl or a boy)   Probability=2C1*4C2/2^4= 2*4/2*2*2*2=8/16=1/2   Ans=1/2
<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 4 children have two children of the same sex and one of the opposite sex?