Dr. Azmawani Abd Rahman (MGM3161)
CHAPTER 9: PERT / CPM PROJECT SCHEDULING WITH KNOWN ACTIVITY Question 1
The Owner of Jusco Puchong Branch is planning to modernize and expands the current facilities. The project is expected to provide room for 8 to 10 new business. The activities and the predecessors are as follows: Activity Activity Description
A B C D E F G H I
Prepare Architectural drawing Identify potential new tenants Develop prospectus for tenants Select contractor Prepare building permits Obtain approval for building permits Perform construction Finalized contracts with tenants Tenants move in
Immediate Predecessor A A A E D,F B,C G ,H
Activity Time (weeks) 5 6 4 3 1 4 14 12 2
1. Draw Draw the the prec precede edenc ncee diagr diagram am 2. How long long will will the the projec projectt take take to comple complete? te? 3. Which activi activities ties are critic critical al and must be completed completed exactly exactly as scheduled scheduled to keep keep the project on schedule? ( identify CRITICAL PATH) 4. How long long can the the noncritical noncritical path activit activities ies be delayed delayed before before they they cause cause an increase in the completion time for the project p roject
Dr. Azmawani Abd Rahman (MGM3161)
PROJECT SCHEDULING WITH UNKNOWN ACTIVITY Question 2
To complete the wing assembly for an experimental aircraft, Asiacraft Company has laid out the major steps and seven activities involved. These activities have been labeled A through G in the following table, which also shows their estimated completion times (in weeks) and immediate predecessors.
a. b. c. d. e.
Activity
a
m
b
A B C D E F G
1 2 4 8 2 4 1
2 3 5 9 5 5 2
3 4 6 10 8 6 3
Immediate predecessors A B C,D B E
Draw the precedence diagram Determine the critical path and the expected project length What is the probability that the project will finish in 17 weeks or less? What is the probability that the project will finish in 18 weeks or less? What is the probability that the project will finish in 20 weeks?
Dr. Azmawani Abd Rahman (MGM3161)
CRASH COST
1. Determine the least cost of reducing the project completion date by 3 months based on the following information A
C Finish
Start
B
D
ACT
E
A B C D E
Normal time (month) 6 7 7 6 9
Crash time Normal (months) cost (RM)
Crash cost
4 5 6 4 8
2400 3500 1300 2600 9000
2000 3000 1000 2000 8800
2. Development of a new deluxe version of a particular software product is being considered by online solution company. The activities necessary for the completion of this project are listed in the following table: Act. A B C D E F G
Normal time (weeks) 4 2 3 8 6 3 4
Crash time (weeks) 3 1 3 4 3 2 2
Normal cost (RM) 2,000 2,200 500 2,300 900 3,000 1,400
Crash cost (RM) 2,600 2,800 500 2,600 1,200 4,200 2,000
Immediate predecessor(s) A B C D,E
1. What is the project completion date? 2. What is the total cost required for completing this project on normal time? 3. If you wish to reduce the time required to complete this project by 1 weeks, which activity should be crashed, and how much will this increase the total cost? 4. If you wish to reduce the time required to complete this project by 5 weeks, which activity should be crashed, and how much will this increase the total cost? 5. What is the maximum time that can be crashed? How much would costs increase?
3. The following table contains information about a project. Shorten the project three weeks by finding the minimum-cost schedule. Assume that project indirect costs and
Dr. Azmawani Abd Rahman (MGM3161)
penalty costs are negligible. Identify activities to crash while minimizing the additional crash costs. Activity A B C D E F G H I
Normal Time (Weeks) 7 12 7 6 1 1 3 3 2
Crash Time (Week) 6 9 6 5 1 1 1 2 2
Cost to crash (RM per week) 200 250 250 300 200 350 -
Immediate Predecessor(s) None None A A B C,D D,E F G
1. What is the project’s duration if only normal times are used? 2. The management wants to shorten the project by 3 weeks. Identify activities to crash while minimizing the additional crash cost and find the additional cost as a result of this activity.
4. Refer to the following information for project X : 7
3
Dr. Azmawani Abd Rahman (MGM3161)
START
E C
Activity A B C D E
2
D
6
END
3
Normal Time (Days) 7 3 6 3 2
Crash Time (Days) 4 2 4 1 1
Normal Cost (RM) 500 200 500 200 300
Crash Cost (RM) 800 350 900 600 550
a. What is the expected completion time? b. If the management wants the project to be completed in 10 days, which activities should be crashed and what is the crash cost? c. If the management want to crash the cost to the maximum, which activities should be crashed, what is the crash cost and what is the total project cost?
