Engineering and Construction

Industrial and Systems Engineering Program
Computer Simulation Systems
IENG 350 – Fall 2016
Assignment 3

Q1: Keuka Park Savings and Loan currently has one drive-in teller window. Cars arrive at a
mean rateof 10 per hour. The mean service rate is 12 cars per hour.
a. What is the probability that the service facility will be idle?
b. If you were to drive up to the facility, how many cars would you expect to see waiting and
being
serviced?
c. What is the average time waiting for service?
d. What is the probability an arriving car will have to wait?
e. What is the probability that more than four vehicles are waiting for service?
f. As a potential customer of the system, would you be satisfied with these waiting-line
characteristics?
g. How do you think managers could go about assessing its customers’ feelings about the
current system?
To improve its customer service, Keuka Park Savings and Loan wants to investigate the effect
of a second drive-in teller window. Assume a mean arrival rate of 10 cars per hour. In addition,
assume a mean service rate of 12 cars per hour for each window. What effect would adding a
new teller window have on the system? Does this system appear acceptable?

Q2: A small local grocery store has one checkout counter. Shoppers arrive at the checkout lane
at an average rate of 15 customers per hour and the average order takes 3 minutes to ring up
and bag.
(a) What information would you develop to help the manager analyze the current operation?
(b) If the manager does not want the average time waiting for service to exceed 5 minutes,
what would you tell him about the current system?
After reviewing the analysis, the manager felt it would be desirable to hire a full-time person to
assist in the checkout operation. The manager believed that if this employee assisted the
cashier, average service time could be reduced to 2 minutes. However, the manager was also
considering installing a second checkout lane, which could be operated by the new person. This
would provide a two-server system with the average service time of 3 minutes for each
customer.
(c) Should the manager use the new employee to assist on the current checkout counter or
to operate a second counter? Justify your recommendation.