A technician monitors a group of five computers that run an automated manufacturing facility. It takes an average of 15 minutes (exponentially distributed) to adjust a computer that develops a problem. The computers run for an average of 85 minutes (Poisson distributed) without requiring adjustments. What is the:
(a) Average number of computers waiting for adjustment?
(b) Average number of computers not in working order?
(c) Probability the system is empty?
(d) Average time in the queue?
(e) Average time in the system?