Probability
posted by Amanda .
From a box containing 7 blue, 5 red, 3 green, and 9 yellow marbles, 2 are drawn one at a time without replacing the first marble before the second marble is drawn. Find the probability that one is blue and one is yellow.

Blue then yellow:
P(BY)=7/24+9/23
Yellow then blue:
P(YB)=9/24+7/23
P(YB∨BY)=P(YB)+P(BY)