Question: Persons arrive at a Xerox machine according to a Poisson process with rate one per minute. The number of copies to be made by each person is uniformly distributed between 1 and 10. Each copy requires 3 sec. Find the average waiting time in queue when:
(a) Each person uses the machine on a first-come first-serve basis.
(b) Persons with no more than 2 copies to make are given nonpreemptive priority over other persons.