4.3. Consider a two-server system in which an arriving customer enters the system if and only if a server is free. Suppose that customers arrive according to a Poisson process of rate A = 10 customers per hour, and that service times are exponentially distributed. The servers have different experience in the job, and the newer server has a mean service time of six minutes, while the older has a mean service time of four minutes. In the long run, what is the rate of customers served per hour? Be explicit about any additional assumptions that you make.