Project Management
The first activity scheduled is activity 2, because it has the minimum slack. Then activity 1 is scheduled. Activity 3 is delayed one period, which reduces slack to zero. From this, activity 5 will also be delayed one period, reducing slack to zero. The remainder of the activities will be scheduled in order, subject to delays.
Therefore, the order in which the activities are scheduled is now 2,1,3,4,5,6.
The activities that are critical are those in which there is the least, or negative, slack. The critical activities therefore are 2,3,5,6.
The slack for activity 1 is now 0. The slack for activity 4 is now 2. The slack for activity 5 is now 0.
Period
Activity
Changes
0-1
Schedule Activity 2 as per minimum slack rule
0-1
Schedule Activity 1
0-1
Delay activity 3 ES to period 1, reduce slack to 0
0-1
Delay activity 5 ES to period 6, reduce slack to 0
1-2
Delay activity 3 ES to period 2, reduce slack to -1
1-2
Delay activity 5 ES to period 7, reduce slack to -1
1-2
Delay activity 6 ES to period 11, reduce slack to -1
2-3
Delay activity 3 ES to period 3, reduce slack to -2
2-3
Delay activity 5 ES to period 8, reduce slack to -2
2-3
Delay activity 6 ES to period 12, reduce slack to -2
3-4
Schedule activity 3
4-5
Schedule activity 4
5-6
No changes
6-7
No changes
7-8
No changes
8-9
5
Schedule activity 5
9-10
No changes
10-11
No changes
11-12
No changes
12-13
6
Schedule activity 6
ID
Res
Dur
ES
LF
SL
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
2
3
0
4
1
2
2
2
2
1
4
0
4
0
1
1
1
1
3
1
5
0,1,2,3
6
1,0,-1,-2
X
X
X
1
1
1
1
1
4
1
6
4
10
0
1
1
1
1
1
1
5
2
4
5,6,7,8
10
1,0,-1,- 2
nx
x2
2
2
2
6
2
3
10,11,12
13
0,-1,- 2
nx2
2
2
3
3
2
2
2
2
2
2
3
3
2
2
2
2
2
RA
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
9.5
The pathway a-D takes 21 weeks; C-E takes 20 weeks; B. takes 8 weeks.
To crash by one week, reduce F. To 5 weeks at a cost of $30 direct costs.
To crash by two weeks, reduce F. To 5 weeks @ $30; reduce D. By 1 week @ $50.
To crash by three weeks, reduce F. By 1 week @ $30; reduce D. By 2 weeks @ $100; reduce C. By 1 week @ $40. This way, a-D takes 19 weeks; C-E takes 19 weeks.
To crash by four weeks, reduce F. By 1 week @ $30, reduce D. By 2 weeks @ $100; reduce a by 1 week @ $80; reduce C. By 1 week @ $40; reduce E. By 1 week @ $100.
To crash by five weeks, reduce F. By 1 week @ $30; reduce D. By 2 weeks @ $100; reduce a by 2 weeks @ $160; reduce C. By 1 week @ $40; reduce E. By 2 weeks @ $200.
This gives us the following cost for each duration:
Duration
Indirect Cost
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