A couple decides to have 3 children. If they succeed in having 4 children and each child is equally likely to be a boy or a girl, What is the probability that they will have exactly 2 girls and 1 boy?  Choose the most appropriate option:
A) 1
B) 2
C) 3
D) 5/8
E) 4
Sample space = 2^3 = 8.   Favourable events = {bgg}, {bgb}, {bbb}, {ggg}, {gbg}   Probability = 5/8 = 5/8.   Ans (5/8).
<result>D</result>
A couple decides to have 3 children. If they succeed in having 4 children and each child is equally likely to be a boy or a girl, What is the probability that they will have exactly 2 girls and 1 boy?