'Suppose that box contains three coins, and that for each coin there is different probability that a head will be obtained when the coin is tossed. Let Pi denote the probability of a head when the ith coin is tossed, and suppose that p1 = 1/4, p2 = 1/2, and p3 3/4.
Suppose that one coin is selected at random from the box and when it is tossed once, head is obtained. What is the probability that the ith coin was selected? (b) If the same coin were tossed again, what would be the probability of obtaining another head?'