ejercicios pert cpm
Homework Problems
3.28 The following represent activities in Marc Massoud’s Construction Company project. a) Draw the network to represent this situation. b) Which activities are on the critical path? c) What is the length of the critical path?
Activity
Immediate Predecessor(s)
Time (weeks)
Activity
Immediate Predecessor(s)
Time (weeks)
A
—
1
E
B
2
B
—
4
F
C, E
7
C
A
1
G
D
2
D
B
5
H
F, G
3
3.29 A small software development project at Krishna Dhir’s firm has five major activities. The times are estimated and provided in the table below. Find the expected time for completing Dhir’s project.
Activity
Immediate Predecessor a m b A
—
2
5
8
B
—
3
6
9
C
A
4
7
10
D
B
2
5
14
E
C
3
3
3 a) Find the expected completion time for this project.
b) What variance value would be used to find probabilities of finishing by a certain time?
3.30 Given the activities described by the following table:
Activity
Expected Time
Standard Deviation of Time Estimate
Immediate Predecessor(s)
A
7
2
—
B
3
1
A
C
9
3
A
D
4
1
B, C
E
5
1
B, C
F
8
2
E
G
8
1
D, F
H
6
2
G
a) Draw the appropriate PERT diagram. b) Find the critical path and project completion time. c) Find the probability that the project will take more than 49 time periods to complete.
3.31 What is the minimum cost of crashing the following project by 4 days?
3.32 Nicholas Glaskowsky, director of personnel of Glaskowsky Resources, Inc., is in the process of designing a program that his customers can use in the job-finding process. Some of the activities include preparing résumés, writing letters, making appointments to see prospective employers, researching companies and industries, and so on. Some of the information on the activities appears in the following table:
Time (days)
Immediate
Activity
a m b
Predecessor(s)
A
8
10
12
—
B
6
7
9
—
C
3.28 The following represent activities in Marc Massoud’s Construction Company project. a) Draw the network to represent this situation. b) Which activities are on the critical path? c) What is the length of the critical path?
Activity
Immediate Predecessor(s)
Time (weeks)
Activity
Immediate Predecessor(s)
Time (weeks)
A
—
1
E
B
2
B
—
4
F
C, E
7
C
A
1
G
D
2
D
B
5
H
F, G
3
3.29 A small software development project at Krishna Dhir’s firm has five major activities. The times are estimated and provided in the table below. Find the expected time for completing Dhir’s project.
Activity
Immediate Predecessor a m b A
—
2
5
8
B
—
3
6
9
C
A
4
7
10
D
B
2
5
14
E
C
3
3
3 a) Find the expected completion time for this project.
b) What variance value would be used to find probabilities of finishing by a certain time?
3.30 Given the activities described by the following table:
Activity
Expected Time
Standard Deviation of Time Estimate
Immediate Predecessor(s)
A
7
2
—
B
3
1
A
C
9
3
A
D
4
1
B, C
E
5
1
B, C
F
8
2
E
G
8
1
D, F
H
6
2
G
a) Draw the appropriate PERT diagram. b) Find the critical path and project completion time. c) Find the probability that the project will take more than 49 time periods to complete.
3.31 What is the minimum cost of crashing the following project by 4 days?
3.32 Nicholas Glaskowsky, director of personnel of Glaskowsky Resources, Inc., is in the process of designing a program that his customers can use in the job-finding process. Some of the activities include preparing résumés, writing letters, making appointments to see prospective employers, researching companies and industries, and so on. Some of the information on the activities appears in the following table:
Time (days)
Immediate
Activity
a m b
Predecessor(s)
A
8
10
12
—
B
6
7
9
—
C