Problem:
Automobiles arrive at a drive through window at a post office at the rate of 4 every 10 mins. The average service time is 2 mins. The poisson distribution is appropriate for the arrival rate and service times are exponentially distributed.
Required:
Question A) what is the average time a car is in the system
Question B) What is the average # of cars in the system
Question C) what is the average # of cars in the system behind the customers recieving service
Question D) what is the % of time that the postal clerk is busy
Question E) what is the probability of 2 or more customers in the system.
Solve the problem and show all work.