The Belgium 20-franc coin (B20), the Italian 500-lire coin (I500), and the Hong-Kong 5-dollar coin (HK5) are appropximately the same size. Coin purse 2 (C2) contains 6 of each of these coins. Coin purse 2 (C2) contains 9 B20's, 6 I500s, and 3 HK5's. A fair four-sided die is rolled. If the outcome is 1, a coin is selected randomly from C1. If the outcome belongs to 2,3,4 a coin is selected from C2. Find

(a) The probability of selecting a Belgium coin (Pr(B20))

(b) The probability that the coin was selected from C1, given that it was a Belgium coin