An average of 10 cars per hour arrive at a single-server drive-in teller. Assume that the average service time for each customer is 4 minutes, and both interarrival times and service times are exponential. Answer the following questions:

1 What is the probability that the teller is idle?

2 What is the average number of cars waiting in line for the teller? (A car that is being served is not considered to be waiting in line.)

3 What is the average amount of time a drive-in customer spends in the bank parking lot (including time in service)?

4 On the average, how many customers per hour will be served by the teller?