Suppose that Ahmed selects a ball by first picking one of the two boxes at random and selecting a ball from this box at random. The first box contains 3 white balls and 2 blue balls, and the second...

Suppose that Ahmed selects a ball by first picking one of the two boxes at random and selecting a ball from this box at random.  The first box contains 3 white balls and 2 blue balls, and the second box contains 1 white balls and 4 blue balls.  What is the probability that Ahmed picked a ball from the second box if he has selected a white ball?