A service center consists of two servers, each working at an exponential rate of two services per hour. If customers arrive at a Poisson rate of three per hour, then, assuming a system capacity of at most three customers,
(a) What fraction of potential customers enter the system?
(b) What would the value of part (a) be if there was only a single server, and his rate was twice as fast (that is, µ = 4)?