question 2 please quickly thanks !!

Two boxes X and Y contain long bolts and short bolts. Suppose that box X contains 30 long bolts and 20 short bolts, and that the other box Y contains 40 long bolts and 10 short bolts. Suppose also that one box is selected at random and a bolt is then selected at random from that box. (1) Determine the probability that this bolt is long. (2) If a long bolt is selected, determine the probability that this long bolt is selected from box Y