7.18 Consider a finite-capacity G/M/1 queueing that allows at most three customers in the system including the customer receiving service. The time to serve a customer is exponentially distributed with mean 1=μ. As usual, let rn denote the probability that n customers are served during an interarrival time, n 5 0; 1; 2; 3, and let fAðtÞ be the PDF of the interarrival times. Find rn in terms of μ and MAðsÞ, where MAðsÞ is the s-transform of fAðtÞ.