Question: Repair calls for copy machines in many offices in a large city are handled by one repair person. Repair time, including the time to travel to the offices, is exponentially distributed, with a mean of two hours per call. Requests for repairs come in at a rate of three per eight-hour-day, Poisson distributed. Note: be careful with units.

a. Determine the average number of customers awaiting repairs, system utilization, the amount of time during an eight-hour day that the repair person is not out on a call, and the probability of two or more customers in the system.

b. Reconsider the problem. Assume the repair person has an assistant, and that the two working together have an average repair time of 1.5 hours, exponentially distributed. Determine the average number of customers awaiting repairs, system utilization, the amount of time during an eight-hour day that the repair person is not out on a call, and the probability of two or more customers in the system.

c. Once again, reconsider the problem. Assume that there are two repair people, and they work separately. Each has an average repair time of two hours per call. And, the calls come into a central office, and are assigned to the next available repair person. Determine the average number of customers awaiting repairs, system utilization, the amount of time during an eight-hour day that the repair person is not out on a call, and the probability of two or more customers in the system.