In a bank drive-through, there is a single service window and room only for two cars to line-up to wait for service. The mean time between arrivals for drive through customers is 5 minutes. The mean time to complete a customer transaction is 3 minutes. The number of arrivals is distributed according to a Poisson distribution and the service times are exponentially distributed.
What is the probability that there are no vehicles in the system?
On average how many cars are in the system?
What is the probability that the system is full and new arrival must drive on?
What is the average time a customer spends in waiting in line to be served?

