A fast food restaurant
Questions
1. A fast food restaurant has customers arrive at the checkout counter at a rate of 35 customers
per hour. The average check out time at the till is 85 seconds. 20 marks
a) What is the utilization?
b) What is probability that there are zero customers at the counter (either in line or being
served)?
c) What is the probability that there are two or more customers at the checkout counter?
d) What is the probability that there are 1 or 2 customers at the counter?
e) What is the average number of customers waiting in line?
f) If the store wanted the average time in the system to be 5 minutes, what would the service rate
have to be?
g) What is the probability that checkout time will take between 1 and 2 minutes?
h) What is the probability that checkout time will take more than 2 minutes?
Operations Management, FARE*3310 – Winter 2022: Assignment 3
2. An operation manager of a chemical manufacturing plant must determine the lot size for a
chemical that has a steady demand of 2,550 litres per day. The production rate is 7,350 litres per
day, setup cost is $700, annual holding cost is $0.22 per litre, and the plant operates 330 days per
year. 20 marks
a. Determine the production order quantity (POQ), the number of orders and the time between
orders. What is the total annual setup cost? What is the total holding cost per year? Using an
appropriately labelled diagram, graph setup cost, holding cost, and total inventory cost, and show
the optimal production order quantity and the minimum total inventory cost. What is the setup
time in hours, based on a $25 per hour setup labour cost?
b. Determine the duration of the active production interval, t. Determine the maximum inventory.
Determine demand during the production interval.
c. As part of its new JIT program, the company has signed a long-term contract with its
customers and the company will take orders electronically for the chemical. The optimal lot size
(production order quantity) will drop to 40,000 litres. Determine the new setup cost per order and
the number of orders (setups). What is the total annual cost of managing the inventory with the
new policy? What is the setup time in hours, based on a $25 per hour setup labour cost with the
new policy?
3. You are asked to determine a location for a recycling depot serving three urban centres. They
are: 20 marks
1. Smallville, population 1,100, at grid location (1.8, 2.8);
2. Bigburg, population 1,900, at grid location (3.5, 8.1); and
3. Middleton, population 1,350, at grid location (7.8, 6.2).
a) Determine the centre of gravity of the three locations.
b) It is determined that planners would prefer to have the depot in either Bigburg or Middleton
(although it will serve all three centres). Using metropolitan distances, determine the loaddistance scores for both Bigburg and Middleton and make a recommendation as to which town
should have the depot.
c) You are asked to provide input on a layout for a new office. The old layout is thought of as
being inefficient. You are asked to redesign the layout and evaluate your redesign using load
distance scores. The current layout is shown below. The overall shape cannot change; you can
merely move the individual departments around. (8 marks)
Operations Management, FARE*3310 – Winter 2022: Assignment 3
E D
C B A
Trips between the different departments are as follows:
A→B : 8 trips per day, A→C : 4, A→D : 7, A→E : 12
B→A : 5, B→C : 2, B→D :5 , B→E : 3
C→A : 3, C→B : 5, C→D : 12, C→E : 3
D→A : 14, D→B : 10, D→C : 4, D→E : 9
E→A : 2, E→B : 3, E→C : 5, E→D : 3
4). 20 marks
a) A toy company is making a decision about ordering a new toy to sell during the holiday
season. They are deciding whether or not to undertake market research to evaluate the potential
market for the product. They have only one opportunity to order the product for this season and
are committed to making either a small order or a large order.
If they choose not to undertake the research, they can make one of two choices: place a large
order or place a small order. If they place an order the probability that demand is high is 50%
and that demand is low is 50%.
If they undertake the market research, the chance that they will get favourable results is 45% and
unfavourable results is 55%. If they get unfavourable results, the probability of high demand is
25% and of low demand is 75%. If they get favourable results, the probability of high demand is
80% and of low demand is 20%. The cost of doing the research is $10,000.
If they place a small order and demand is low the net return is $10,000. If they place a small
order and demand is high the net return is $100,000. If they place a large order and demand is
low the return is $-50,000. If they place a large order and demand is high the net return is
$200,000.
What are the right decisions for the firm to make relative to the market research and the size of
the order?
b) Now consider only the “no market research” branch of your decision tree (there should be
one). If someone could tell you definitively whether demand would be high or low (without
doing market research), what would be the value of knowing (i.e. the expected value of perfect
information).
Operations Management, FARE*3310 – Winter 2022: Assignment 3
5. A small Caribbean airline has been receiving complaints about its airport check-in procedure.
You are asked to provide input into the process. You find that they have six people assigned to
checking in passengers. 15 marks The steps are:
1. Check documents – 4 minutes
2. Check in, boarding pass – 6 minutes
3. Security check in – 10 minutes
4. Customs preparation – 4 minutes
5. Manual security check – 8 minutes
6. Collect boarding pass – 1 min
a) Draw the flow diagram and include cycle times and capacity.
b) Where is the bottle neck?
c) What is system capacity and efficiency?
d) How might you improve the capacity and efficiency without adding more staff? What is
your new capacity and efficiency? Where is the bottle neck?
Operations Management, FARE*3310 – Winter 2022: Assignment 3
6. The operations manager for Fine Foods Distribution has narrowed the search for a new
facility to seven communities. Fixed costs (land, buildings, and equipment) and variable
costs (labour, materials etc.) are shown below. 15 marks
Distribution Centre Costs
Community Fixed Costs ($millions) Variable Costs ($)
Aurora $1,600 17
Boulder 2,000 12
Cranbrook 1,500 16
Deerfield 3,000 10
Essex 1,800 15
Farber 1,200 15
Grafton 1,700 14
a. Which of the communities can be eliminated from further consideration
because they are dominated (both variable and fixed costs are higher) by
another community?
b. Plot the total cost curves for all remaining communities on a single graph.
Identify on the graph the approximate range over which each community
provides the lowest cost.
c. Using locational break-even analysis, calculate the break-even quantities to
determine the range over which each community provides the lowest cost.