Eight maintenance activities, their normal durations in weeks, and the crew sizes for the normal condition are as follows:
|
Activity
|
Duration in weeks
|
Crew size
|
|
AC
|
6
|
8
|
|
BC
|
6
|
7
|
|
BE
|
2
|
6
|
|
CD
|
3
|
2
|
|
CE
|
4
|
1
|
|
DF
|
7
|
4
|
|
EF
|
4
|
6
|
|
FG
|
5
|
10
|
(a) Represent the maintenance project in the form of an activity-event network.
(b) Identify the critical path and find the minimum time for project completion.
(c) Extra crew members can be used to expedite activities BC, CE, DF, and EF at a cost given below:
|
Extra Crew
|
Weeks Saved
|
Crash Cost per Week ($)
|
|
1
|
1
|
100
|
|
2
|
2
|
120
|
|
3
|
2
|
200
|
|
4
|
3
|
250
|
If there is a penalty cost of $1,250 per week beyond the minimum maintenance time of 17 weeks, recommend the minimum-cost schedule.