4) (10) A post office is serviced by n clerks. The time clerk i spends serving a customer X, has the exponential distribution X1~Exp(1),i = 1,2 ...n (All the X's are independent and identically distributed) Let M = min (X1, X2, ... Xn) a) Find the CDF of M. (Hint: Start with the probability P(M>m), and then use that to find the CDF by subtracting from 1). b) What distribution does M follow? Find E(M). Give an intuitive idea why M follows the distribution it does. c) Special case---A post office has two clerks, with the same assumptions as above. A enters the post office while 2 other customers B, and C, are being served. A is next in line. What is the expected total time A needs to spend at the post office? (Hint: No Integrals needed)