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?

If there were a box of babies and 3 were boys and four were girls, the probability would be 4/7 (Right? Make a fool of me if that's wrong) but it says nothing about where the baby being added came from or how many babies there were of each gender, so it's really 50:50. The probability is 1/2

Posted by Sara on 2003-11-10 19:17:32