On a county road there is a gas pump. Vehicle arrivals at jet are produced according to a Poisson process of mean 10 an hour while the Average service time is 4 minutes per customer, this being exponential. a) Calculate the probability that when a vehicle arrives, the pump is empty. b) When a vehicle arrives in the system, what is the expected number of vehicles that find it in the queue? c) Calculate the average time of a car in the service station