Chance of Having Two Boys - The Answer

(Solution Hidden)

Here is the answer to the Chance of Having Two Boys:

If someone has 2 children, there are 4 possibilities:

1. Boy - Girl

2. Boy - Boy

3. Girl - Girl

4. Girl - Boy

In the case of the woman, we are told that she has at least one boy. This rules out possibility #3, and thus leaves 3 possibilities (#1, #2, and #4). Of these 3 possibilities, only one (#2) has a second boy.

Thus, there is a 1 in 3 chance that the woman has another boy.


In the case of the man, we are told that his oldest child is a boy. This rules out both cases #3 and #4. This leaves cases #1, and #2. Only case #2 has both boys.

Thus, there is a 1 in 2 chance that the man has another boy.