(1) drexel national bank is considering opening a drive-through window for customer service. management estimates that customers will arrive at the rate of 10 per hour. the teller who will staff the window can serve customers at the rate of one every four minutes. assuming poisson arrivals and exponential service, find (a) average number of customers in the system. (b) average time in the system. (c) average waiting time in the line. (d) average number of customers in the line. (e) utilization of the teller.