A New 24-Hour Pharmacy Is Opened in a Busy Intersection

Essay

A new 24-hour pharmacy is opened in a busy intersection by the Blue-Green Pharmacy chain. Customers come into the system at a rate of 15 per hour; at all times, there are 2 pharmacists who can each serve at the rate of 10 per hour. Arrivals are Poisson, and service is exponential. Find the following operating characteristics of the system
(A) average number of customers in the system
(B) average waiting time in the system
(C) the probability of having 3 customers in the system