Let us consider a small "Car Wash System"
being considered by an entrepreneur as a start up.
He did a small survey and found that on the average
one customer, arrives every eight minute. However
the car wash equipment requires a flat 10 minutes
for any car. He also found that any customer who is
likely to wait beyond 5 minutes is unlikely to stay
in the queue and may go away. He was determined to
retain all his customers and service them well, such
that they need not wait for more than 5 minutes. He
plans to operate one shift of 8 hours to start with.
He requires quick answer as to the number of washing
bays required to meet the service level expected,
to plan and justify his investment.