Answer : 1. "1/3"
Explanation :

Answer: A) 1/3 Explanation: In a family with 2 children there are four possibilities:1) the first child is a boy and the second child is a boy (bb)2) the first child is a boy and the second child is a girl (bg)3) the first child is a girl and the second child is a boy (gb)4) the first child is a girl and the second child is a girl (gg) But already given that one child is boy. So we have three possibilities of (bb)(bg)(gb).n(E)= both are boys=BB=1n(S)= 3Required probability P = n(E)/n(S) = 1/3.