QBPA : Quantitative Business Process Analysis

Example $6$b : Queueing Theory $-$ Solve the Queuing M $/$ M $/1$ & M $/$ M $/2$ Systems

A small bank has two tellers, who are equally efficient and who are each capable of

handling an average of $60$ customer transactions per hour, with the actual service times

exponentially distributed. Customers arrive at the bank according to a Poisson process, at a

mean rate of $100$ per hour. What is the percentage increase in the length of time a customer

should expect to spend at the bank if one of the tellers quit the job?