Customer arrives at a one window drive in bank according to poisson distribution with mean 10 per hour. Service time per customer is exponential with mean 5 minutes. the space in front of window, including that for serviced car can accommodate a maximum of three cars. other cars wait outside this space
(a) What is the probability that arriving customer can drive directly to the space in front of the window.
(b) What is the probability that arriving customer will have to wait outside the indicated space.
(c) How long is an arriving customer will have to wait before starting service.