Project Management Chapter 4 Q7

Question 3 (35 marks) - Words: 2 – 2.5 Pages

The R&D department is planning to bid on a large project for the development of a new communication system for commercial planes. The accompanying table shows the activities, time, and sequences required;

Activity
Immediate Predecessor
Time (Weeks)
A
--
3
B
A
2
C
A
4
D
A
4
E
B
6
F
C,D
6
G
D,F
2
H
D
3
I
E,G,H
3

a. Draw the network diagram.
b. What is the critical path?
c. Suppose you want to shorten the completion time as much as possible, and you have the option of shortening any or all of B,C,D and G each one week. Which would you shorten?
d. What is the new critical path and earliest completion time?

Question 3a

Question 3b
From the above project network, five possible paths found in that project as below table:
Path number
Path Details
Time required (Per Week)
1
A > B > E > I
3 + 2 + 6 + 3 = 14
2
A > C > F > G > I
3 + 4 + 6 + 2 + 3 = 18
3
A > D > F > G > I
3 + 4 + 6 + 2 + 3 = 18
4
A > D > G > I
3 + 4 + 2 + 3 = 12
5
A > D > H > I
3 + 4 + 3 + 3 = 13

As the duration of path 2(ACFGI) and 3(ADFGI) need 18 weeks to complete the project which is longest time, so the path 2 and 3 are critical path.

Question 3c
As the activity B does not located on critical path, therefore the completion time no change even its shorten one week. For the activity G which is located on both critical path 2(ACFGI) and 3(ADFGI), therefore it is key activity for the project and has to shorten. Due to activity C and D is location on critical path 2(ACFGI) and 3(ADFGI) respectively, if only shorten activity C or D then another one become critical path, therefore both activity C and D have to shorten one week at same time. Conclusion, I would choose activity C, D and G to shorten the completion time as above reasons.

Question 3d
The new critical path is (ACFGI) or (ADFGI) and the earliest completion time is 16 weeks. Although the path 2 and 3 has same result as no need to consider the additional cost for shorten related activity, in realty