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After crashing activity B by one week, we apply the critical path method and obtain the following information about the project.
| Activity | New Activity times(weeks) | ES | EF | LS | LF | Slack | Critical |
| Start | 0 | 0 | 0 | 0 | 0 | 0 | yes |
| a | 6 | 0 | 6 | 1 | 7 | 1 | no |
| b | 7 | 0 | 7 | 0 | 7 | 0 | yes |
| c | 4 | 0 | 4 | 0 | 4 | 0 | yes |
| d | 5 | 7 | 12 | 7 | 12 | 0 | yes |
| e | 8 | 4 | 12 | 4 | 12 | 0 | yes |
| end | 0 | 12 | 12 | 12 | 12 | 0 | yes |
The precedence relations, crash durations, and crash costs of activities of this project were introduced in the lecture.
Which activity or activities should be crashed to reduce the project duration to 11 weeks?
Expert Answer
Therefore next activity should be crashed from any of b,c,d or e.
The activity which has the minimum amount of crash slope or crash cost per week must be crashed first.
We see that there are three alternative paths a-d. b-d and c-e. activity a is non-critical.
Therefore any one activity from the critical paths i.e. b-d and c-e must be crashed. These two critical paths do not have any common activity. Therefore two activities need to be crashed simultaneously, one from each path.
one activity to be crashed is either b or d, whichever has the lowest crash cost per week.
The other actiivty to be crashed is either c or e, which has the lowest crash cost per week.
