Queuing problem:Single server
(a) Consider a coffee counter with a single server at which tired students arrive according to a Poisson process. Let the mean arrival rate be two students per ten minutes and assume the serving time is exponentially distributed with an average of 180 seconds per student.
1. What is the average queue length?
2. How long does a student have to wait in the queue?
3. Find the average queue length and waiting time in the queue if the service time decreases to 120 seconds per student.
(b) The owner of a shop observes that on average 18 customers per hour arrive and there are typically 8 customers in the shop. What is the average length of time each customer spends in the shop?