Chapter 4 & 5 Test Questions
1. chandise for the holiday
season.
The store prices are so appealing that lines of people queue up in the early AM hours in front of the
store doors in order to secure a place in the line.
On the morning after Thanksgiving, one of the busiest days of the year, the store opened its doors
at 8:00AM. At that time there were 120 customers already waiting in line. From 8:00AM to
10:00AM, new customers arrive at the rate of 5 per minute. After 10:00AM, the rate reduces to 2
per minute. The store admits customers at the rate of 4 per minute.
a. Jacob plans to arrive to the store at 9:00AM. How long should he expect to wait?
b. Rachel does not want to wait more than 15 minutes. When should she show up?
2. EZS is a small fast food outlet located in midtown Manhattan and serving mainly the
supplemented with an assortment of drinks, light salads, seasonal fruit and snacks. The
restaurant is open 10:00AM to 10:00PM, but the peak demand is during lunch hours, 11:30 to
2:00PM.
A customer joining the line makes a sandwich selection by consulting the billboard, marks her
selection on a customized form, and hands the form to one of several assemblers who produce
the sandwich. The customer does not wait for the sandwich to be assembled, but proceeds
directly down the line to select additional items onto her tray. Next, the customer proceeds to
pay at the cash register. Finally, (after the payment is completed) she collects her prepared
sandwich at a designated location.
Selecting the sandwich and marking the form takes 45 seconds. Assembling the sandwich
requires 90 seconds. Selecting additional items takes 60 seconds. Paying at the cash register
requires 40 seconds. Collecting the prepared sandwich requires 20 seconds. The restaurant
employs 2 cash registers and 6 sandwich assemblers, and one person to disburse the prepared
sandwiches.
a. Draw a process map
b. What is the theoretical flow time of the process?
c. What is the capacity of the process
d. During rush hour, demand exceeds capacity and long lines form. Does it make sense
to add a sandwich assembler?
3.
various customers on a short term basis. The typical tour of duty lasts for 7 weeks, and the period
between assignments typically lasts for 3 weeks. Assume 50 weeks per year.
a. On average, how many specialists start on a new assignment each week?
b. On average, how many specialists are idle (between assignments)?
4.
Revenue 700
COGS 400
SGA&O 200
Profit 100
It is estimated that 20% of COGS and 10% of SGA&A are Throughput Cost (vary with
throughput), and the rest are Capacity Cost ( fixed with respect to throughput). The throughput
is 100,000 units per year.
a. What will be the increase in profit if throughput increases by 1%?
Exam Solutions:
Problem 1:
Problem 2:
c. Capacity per minute:
Problem 3:
Problem 4:
a. First we need to separate the total cost (COGS +SGA&O) into throughput cost and capacity
cost
