25. Customers arrive at a service station, manned by a single server who serves at an exponential rate ì÷, at a Poisson rate A. After completion of service the customer then joins a second system where the server serves at an exponential rate ì2. Such a system is called a tandem or sequential queueing system. Assuming that A < ì,, / = 1,2, determine the limiting probabilities.

Hint: Try a solution of the form Pnm = Canßm, and determine C, á, â.