Let the service center consisting of two servers, each working at the exponential rate of two customers served per hour. Suppose customers arrive to service center according to possion rate of three per hour, and service center can hold at most four customers.

a) Find fraction of potential customers enter system?

b) Find would be answer to part(a) if there were only single server which can serve customers twice as fast (i.e, with service rate four customers per hour)?

c) Now assume that service center consists of two separate lines, one for each server. Each line can hold at most customers, including custommer being served. for simplicity, suppose that arriving customer selects line uniformly at random. If line they selected is full, customer leaves. For this system, compute the fraction of potential customers that enter system.