Futility Closet

Boy Trouble

Posted in Puzzles, Science & Math by Greg Ross on September 5th, 2007

I have two children, and at least one of them is a son. What is the probability that the other is also a son?

The answer is not 1/2. There's no trick here; like the Monty Hall problem, it's just a case where common sense is wrong.

I'll give the solution tomorrow.