for a costumer at server i is exponentially distributed with rate 4, / - 1, 2. Different service times are independent. An arriving customer finding server 1 busy waits in line for that gerver. Upon completion of service at server 1, a customer either enters service with server 2 if that server is free or else remains with server 1 (blocking any other customer from entering service) until server 2 is free. Customers depart the system after being served by server 2. Suppose that, when you arrive, there are exactly two customers in the system, one being served by server 1