Mr. D. Inc. operates an auto repair shop. Arrivals of jobs at the shop has Poisson distribution with arrival rate of 3 jobs per 8-hour day. Time to complete jobs is a normal probability distribution with a mean time of 3.4 hours and standard deviation of 2.1 hours.
Compute the following:
(a) Average number of jobs waiting for service.
(b) Average time a job waits before a worker can begin working on it.
(c) Average number of hours between when a job is received and when it is completed.
(d) Percentage of time the auto worker is busy.