Let's Hear it for the Boys
RAY: There are four possible scenarios: Older boy, younger boy. Older boy, younger girl. Older girl, younger boy. And older girl, younger girl. Now, in the first case, when I say the older one is a boy, that immediately leaves out the last two possibilities. It can only be boy-boy or boy-girl. So, in order for the other one to be a boy, it's a 50-50 chance.
TOM: That's right.
RAY: Now,when I say that one of them is a boy, it becomes harder for the other one to become a boy. And the chances are one in three. If you look at the scenarios, you have boy-boy, boy-girl and girl-boy. For the other one to be a boy, it's gotta be choice #1 which is boy-boy. There's one chance in three. Do we have a winner this week?
TOM: Yes, we do. The winner is David Ward from Atlanta, Georgia. Congratulations!
[ Car Talk Puzzler ]