I'm confused by your comment but I'll try to explain more. Given one of the children is a boy. The only combinations possible are: GB, BG, & BB. Where G is Gir

I'm confused by your comment but I'll try to explain more. Given one of the children is a boy. The only combinations possible are: GB, BG, & BB. Where G is Girl and B is Boy. The question is about the probability of the other child being a Girl. When we eliminate one of the B from each combination, we get: GB, BG, BB -> G, G, B We can see that 2/3 are G and 1/3 are B. Does this help?