there are two urns. the first urn has 2 black balls and 1 white ball inside and there are 2 black balls and 2 white balls in the second urn. you ask your friend to randomly choose an urn and pick 2 balls one by one with no replacement. 1c) if one black and one white ball are selected, what is the probability that your friend select the urn with 3 balls inside?
