"An urn contains one white chip and a second chip that is equally likely to be white or black. A chip is drawn at random and returned to the urn. Then a second chip is drawn. What is the probability that a white appears on the second draw given that a white appeared on the first draw"?
I keep getting answer 3/4 but it is incorrect. I tried calculating P(A|B) directly; also, I looked at the case where both chips were white then one was black and I averaged those. I always got 3/4.
Personally, I don't even see how the first drawing has any affect on the latter.