Jun 21, 2014
RAY: Here’s the first half of the puzzler: If a mother has two kids and the older one is a boy, what are the chances the younger is a boy?
TOM: I know this puzzler. This is a killer.
RAY: And the answer is 50-50. So I'll give you that part. Now, suppose a different mother has two kids and one of them is a boy. What are the chances that the other one is a boy? Well, it's got to be 50-50, right?
TOM: You would think.
RAY: Wrong.
TOM: Of course.
RAY: So, what are those chances?
TOM: I know this puzzler. This is a killer.
RAY: And the answer is 50-50. So I'll give you that part. Now, suppose a different mother has two kids and one of them is a boy. What are the chances that the other one is a boy? Well, it's got to be 50-50, right?
TOM: You would think.
RAY: Wrong.
TOM: Of course.
RAY: So, what are those chances?
Answer:
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!
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!
