Response to the following problem:
Bronco Burger has a drive-thru window for take-out orders. Because of space limitation, the restaurant has been designed to allow a maximum of 5 cars in the drivethru window line (including the car being served). If the line is full, cars will not stop at Bronco Burger but will instead drive to a competing restaurant. Cars attempt to arrive to Bronco Burger's drive-thru window at an average of one every 80 seconds.
Interarrival times are assumed to follow an exponential distribution, hervice times also follow an exponential distribution, with a mean service time of one minute.
a. What is the average number of cars waiting in line for service?
b. What is the average time a car spends in line, including the service?
c. What is the probability that there are no cars at the drive-thru window?
d. Comment on the appropriateness of modeling the service time at Bronco Burger by an exponential distribution.