4.126 Waiting Times Suppose that at a particular supermarket the probability of waiting 5 minutes or longer for checkout at the cashier's counter is 0.2. On a given day, a husband and wife decide to shop individually at the market, each checking out at differ- ent cashier counters. They both reach cashier counters at the same time.

a. What is the probability that the man will wait less than 5 minutes for checkout?

b. What is probability that both of them will be checked out in less than 5 minutes? (Assume that the checkout times for the two are independent events.)

c. What is the probability that one or the other or both will wait 5 minutes or longer?