Chapter 11 Complete Problems 1 & 7 (Chapter 11) 1. Willow Brook National Bank operates a drive-up teller window that allows customers to complete bank transactions without getting out of their cars. On weekday mornings, arrivals to the drive-up teller window occur at random, with an arrival rate of 24 customers per hour or 0.4 customer per minute. a. What is the mean or expected number of customers that will arrive in a five-minute period? b. Assume that the Poisson probability distribution can be used to describe the arrival process. Use the arrival rate in part (a) and compute the probabilities that exactly 0, 1, 2, and 3 customers will arrive during a five-minute period. c. Delays are expected if more than three customers arrive during any five-minute period. What is the probability that delays will occur? 7. Speedy Oil provides a single-channel automobile oil change and lubrication service. Customers provide an arrival rate of 2.5 cars per hour. The service rate is 5 cars per hour. Assume that arrivals follow a Poisson probability distribution and that service times fol- low an exponential probability distribution. a. What is the average number of cars in the system? b. What is the average time that a car waits for the oil and lubrication service to begin? c. What is the average time a car spends in the system? d. What is the probability that an arrival has to wait for service