Problem 9.3.

In a departmental store one cashier is there to serve the customers. And the customers pick up

their needs by themselves. The arrival rate is 9 customers for every 5 minutes and the cashier can serve

10 customers in 5 minutes. Assuming Poisson arrival rate and exponential distribution for service rate,

find:

(a) Average number of customers in the system.

(b) Average number of customers in the queue or average queue length.

(c) Average time a customer spends in the system.

(d) Average time a customer waits before being served.