SOLUTION MANUAL FOR
OPERATIONS MANAGEMENT
PROCESSES AND SUPPLY CHAINS,
13E LEE KRAJEWSKI, MANOJ
MALHOTRA
,DISCUSSION QUESTIONS
Chapter
1.
5 Constraint Management
Examples of everyday bottlenecks include traffic lights, drive-thru windows at the
bank or fast food restaurants. On the highway merging lanes and speed zones.
Efficiency can be improved by maintaining constant speeds, setting traffic lights to
coordinate traffic patterns and only allowing highway construction after rush hour.
Fast food restaurants have two windows, pull over spots and new cash card options
to reduce time at the window.
2. A change in demand can easily shift bottlenecks. For instance, fast food restaurants
can provide promotional pricing on certain types of sandwiches or fries, which
would make their workstations take longer than normal and become capacity
constrained. Banks can provide incentives for new accounts to be opened, causing
bottlenecks at teller windows where none existed before.
3. There are many ways that process efficiency may be improved further. In the case
of our banking example, a manager might: (1) reduce processing time by providing
forms to be filled out by the customer before the customer reaches the teller
window, (2) reduce processing variability by restricting each customer to three
transactions, (3) reduce the arrival variability of customers by requiring that
5-1
, 5-2 PART 1 Managing Processes
customers make an appointment to see a teller, (4) add resource capacity by
increasing the number of tellers during busy periods, (5) improve resource
flexibility by ensuring that all tellers are cross trained and will help co-workers with
complex transactions, (6) improve resource availability by restricting lunch and
break time for tellers, (7) coordinate the movement of customers by making sure
that all teller windows are available to all arriving customers, (8) outsource non-
value-adding activities such as rework by rerouting difficult customers to branch
management, and (9) create standardized work procedures for routine, non-complex
processes.
PROBLEMS
Managing Bottlenecks in Service Processes
1. Bill’s Barbershop
a. 10 + 8 + (15+10)/2 + 9 = 39.5 minutes
b. Step B1 is the bottleneck, it can only handle 6 customers per hour while the rest of
the steps can handle 7.5, 10 (60/10 +60/15), and 6.67 customers per hour.
c. This process is limited by step B1, therefore the entire process can only serve 6
customers per hour.
2. Melissa’s Photo Studio
a. 5 + (5+7)2 + 20 + 7 = 38 min
b. Taking group portraits is the bottleneck for the entire process. Only 3 group
portraits can be taken per hour.
c. Groups bottleneck is taking the portrait the bottleneck time is 20 min which
yields a capacity of 60/20 or 3 per hour. Individuals bottleneck is taking the
portrait which has a processing time of 15 min, which yields a capacity of 60/15
or 4 per hour.
3. Barbara’s Boutique
a. 3 [the bottleneck is step T4 at 18 minutes – 3.33 customers per hour or 3]
b. Step T6 at 22 minutes limits Type B to 60/22 = 2.73 customers/hr.
c. 3.33(.3) + 2.73(.7) = 2.91 customers on average
With an arrival rate greater than 5 customers per hour into the process, then type A
customers may wait at step T1, T2 and T4. Waiting occurs at these steps because
the arrival rate of customers into their step is greater than that step’s processing rate.
Also assuming that the arrival rate is greater than 5 customers per hour, type B
customers may wait steps T1, T5, and T6 because these steps’ processing times are
slower than the processing time of their immediate preceding steps.
Managing Bottlenecks in Manufacturing Processes
4. CKC
Station X is the bottleneck – 2600 minutes
OPERATIONS MANAGEMENT
PROCESSES AND SUPPLY CHAINS,
13E LEE KRAJEWSKI, MANOJ
MALHOTRA
,DISCUSSION QUESTIONS
Chapter
1.
5 Constraint Management
Examples of everyday bottlenecks include traffic lights, drive-thru windows at the
bank or fast food restaurants. On the highway merging lanes and speed zones.
Efficiency can be improved by maintaining constant speeds, setting traffic lights to
coordinate traffic patterns and only allowing highway construction after rush hour.
Fast food restaurants have two windows, pull over spots and new cash card options
to reduce time at the window.
2. A change in demand can easily shift bottlenecks. For instance, fast food restaurants
can provide promotional pricing on certain types of sandwiches or fries, which
would make their workstations take longer than normal and become capacity
constrained. Banks can provide incentives for new accounts to be opened, causing
bottlenecks at teller windows where none existed before.
3. There are many ways that process efficiency may be improved further. In the case
of our banking example, a manager might: (1) reduce processing time by providing
forms to be filled out by the customer before the customer reaches the teller
window, (2) reduce processing variability by restricting each customer to three
transactions, (3) reduce the arrival variability of customers by requiring that
5-1
, 5-2 PART 1 Managing Processes
customers make an appointment to see a teller, (4) add resource capacity by
increasing the number of tellers during busy periods, (5) improve resource
flexibility by ensuring that all tellers are cross trained and will help co-workers with
complex transactions, (6) improve resource availability by restricting lunch and
break time for tellers, (7) coordinate the movement of customers by making sure
that all teller windows are available to all arriving customers, (8) outsource non-
value-adding activities such as rework by rerouting difficult customers to branch
management, and (9) create standardized work procedures for routine, non-complex
processes.
PROBLEMS
Managing Bottlenecks in Service Processes
1. Bill’s Barbershop
a. 10 + 8 + (15+10)/2 + 9 = 39.5 minutes
b. Step B1 is the bottleneck, it can only handle 6 customers per hour while the rest of
the steps can handle 7.5, 10 (60/10 +60/15), and 6.67 customers per hour.
c. This process is limited by step B1, therefore the entire process can only serve 6
customers per hour.
2. Melissa’s Photo Studio
a. 5 + (5+7)2 + 20 + 7 = 38 min
b. Taking group portraits is the bottleneck for the entire process. Only 3 group
portraits can be taken per hour.
c. Groups bottleneck is taking the portrait the bottleneck time is 20 min which
yields a capacity of 60/20 or 3 per hour. Individuals bottleneck is taking the
portrait which has a processing time of 15 min, which yields a capacity of 60/15
or 4 per hour.
3. Barbara’s Boutique
a. 3 [the bottleneck is step T4 at 18 minutes – 3.33 customers per hour or 3]
b. Step T6 at 22 minutes limits Type B to 60/22 = 2.73 customers/hr.
c. 3.33(.3) + 2.73(.7) = 2.91 customers on average
With an arrival rate greater than 5 customers per hour into the process, then type A
customers may wait at step T1, T2 and T4. Waiting occurs at these steps because
the arrival rate of customers into their step is greater than that step’s processing rate.
Also assuming that the arrival rate is greater than 5 customers per hour, type B
customers may wait steps T1, T5, and T6 because these steps’ processing times are
slower than the processing time of their immediate preceding steps.
Managing Bottlenecks in Manufacturing Processes
4. CKC
Station X is the bottleneck – 2600 minutes
