Question 4: This question has two sections. Section A, and Section B
Section A:
A partially solved PERT problem is detailed in the table below. Times are given in weeks.
|
Activity |
Preceding |
Optimistic Time |
Probable Time |
Pessimistic Time |
Expected Time |
Variance |
|
A |
— |
7 |
9 |
14 |
1.361 |
|
|
B |
A |
2 |
2 |
8 |
0 |
|
|
C |
A |
8 |
12 |
16 |
0 |
|
|
D |
A |
3 |
5 |
10 |
1.361 |
|
|
E |
B |
4 |
6 |
8 |
0 |
|
|
F |
B |
6 |
8 |
10 |
0 |
|
|
G |
C, F |
2 |
3 |
4 |
0 |
|
|
H |
D |
2 |
2 |
8 |
1.000 |
|
|
I |
H |
6 |
8 |
16 |
2.778 |
|
|
J |
G, I |
4 |
6 |
14 |
2.778 |
|
|
K |
E, J |
2 |
2 |
5 |
0.250 |
Which activities form the critical path? What is the estimated time of the critical path? What is the probability of completion of the project after week 40?
Section B:
A simple network has three activities, D, E, and F. D is an immediate predecessor of E and of F. E is an immediate predecessor of F. The activity durations are , , . Calculate the critical path and the number of days?
