One field representative services five customers for a computer manufacturer. Customers request assistance at an average (Poisson-distributed) rate of once every four working days. The field representative can handle an average (Poisson-distributed) of one call per day. Determine:

a. The expected number of customers waiting.

b. The average length of time customers must wait from the initial request for service until the service has been completed.

c. The percentage of time the service rep will be idle.

d. By how much would your answer to part a be reduced if a second field rep were added?