Speedy Oil provides a single-server automobile oil change and lubrication service. Customers provide an arrival rate of 2.5 cars per hour. The service rate is 5 cars per hour. Assume that arrivals follow a Poisson probability distribution and that service times follow an exponential probability distribution.
a. What is the average number of cars in the system?
b. What is the average time that a car waits for the oil and lubrication service to begin?
c. What is the average time a car spends in the system?
d. What is the probability that an arrival has to wait for service?