Time-Cost Trade-Offs
|
Activity
|
Predecessor
|
Total Normal time (day)
|
Total Crash time (day)
|
Total Normal cost ($)
|
Total Crash cost ($)
|
Available crashing days
|
Crashing cost per day (cost slope)
|
|
A
|
---
|
6
|
5
|
60
|
90
|
|
|
|
B
|
---
|
7
|
4
|
50
|
150
|
|
|
|
C
|
A
|
6
|
4
|
100
|
200
|
|
|
|
D
|
A
|
7
|
7
|
30
|
30
|
|
|
|
E
|
B
|
5
|
4
|
70
|
85
|
|
|
|
F
|
C
|
9
|
7
|
40
|
120
|
|
|
|
G
|
E, D
|
7
|
4
|
50
|
230
|
|
|
Overhead project costs (Indirect costs) are $70 per day.
Please crash the project and find the project schedule with the lowest total cost (indirect cost + direct cost).
Rule of thumb:
Crash the project one period at a time.
Crash the least expensive activity that is on the critical path.
Critical path will very likely change after each crashing, find new critical path each time before crashing.