The following figure is a brief answer, please explain the meaning of each formula in detail.

17.4-7. Consider a two-server queueing system where all service times are independent and identically distributed according to an exponential distribution with a mean of 10 minutes. Service is pro- vided on a first-come-first-served basis. When a particular customer arrives, he finds that both servers are busy and no one is waiting in the queue. (a) What is the probability distribution (including its mean and standard deviation) of this customer's waiting time in the queue? (b) Determine the expected value and standard deviation of this customer's waiting time in the system. (c) Suppose that this customer still is waiting in the queue 5 min- utes after its arrival. Given this information, how does this change the expected value and the standard deviation of this customer's total waiting time in the system from the answers obtained in part (b)? 17.4-7. (a) This customer's waiting time is exponentially distributed with a mean of 5 minutes. (b) The total waiting time of the customer in the system is W = W, +Ts, where W, and Ts are independent from each other. E(W) = E(W) + E(T ) = 5 + 10 = 15 minutes = 1/4 hour = = = 2 var(W) = var(W) + var(T.) = (*) * + ()? ) 2 = = = 0.0347 12 6. (c) W = 5+W E(W) = 20 minutes, var(W) = 0.0347