Critical path is;
1-2-3-4-6
∴= 20days
Associated Total Cost
Total normal cost + total indirect cost
Total normal cost:
2,800,000
4,000,000
2,200,000
1,600,000
0
1,800,000
5,000,000
1,000,000
Total 18,400,000
Total Indirect Cost
Sh.600,000 x 20days
Sh.12,000,000
Total cost:
12,000,000
18,400,000
30,400,000
(ii) The minimum duration and the coresponding total cost.
Network diagram;using minimum durations.
Critical path is 12 days
Total Crash cost
Total normal Cost:
3,800,000
5,600,000
3,000,000
2,800,000
0
3,200,000
7,000,000
1,600,000
Total 27,000,000
Total Indirect cost
600,000x12days
7,200,000
Total cost
7,200,000
27,000,000
Total 34,200,000
(iii) The optimum duration and thc corresponding total cost.
The original critical path is
1 - 2 - 3 - 4 - 6
Critical activity
|
Cost Shs per day
|
Duration Crash by
days |
Rank |
1-2 |
500 |
2 |
3 |
2-3 |
400 |
2 |
2 |
3 - 4 |
0 |
0 |
1 |
4 - 6 |
500 |
4 |
3 |
Note;
Cost slope
=
Crash cost - Normal cost
Normal time - Crash time
Paths / Days |
Duration |
Critical |
1 - 2 - 3 - 4 - 6 |
20 |
Yes |
1 - 2 - 4 - 6 |
19 |
No |
1 - 3 - 4 - 6 |
18 |
No |
1 - 3 - 5 - 6 |
17 |
No |
Hence maximum crash time is 2 days for the activity 2 - 3 so as to give the minimum cost of
18,400,000 + (2 x 400,000) + 18 x 600,000 = Sh.30,000,000
Therefore, the optimal duration is 18 days with a total cost of sh. 30,000,000