A baby is added to a hospital nursery. Before the baby was added there were two boys in the nursery and an uncounted number of girls. After the new baby is added a baby is selected at random among all the babies. The selected baby is a boy.

What is the probability that the added baby was a girl?

(In reply to re: I have not read Charlie's post yet by Charlie)

This looks like another case of me not really grasping the ground rules (and I do not want ot start another "marbles bonanza"- style circus) I just had always been taught that nothing that happens after an event can effect the likelyhood of that event. (once the coin is tossed it stays tossed)
Anyway, I see what you are saying andthat I was laboring under some misconceptions again.

Posted by FatBoy on 2003-10-09 07:33:47