just to let you know i won\'t rate until i check the grade after i post the answ
ID: 434314 • Letter: J
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just to let you know i won't rate until i check the grade after i post the answer. I am tired of the people answering without knowledge or just by guessing
just to let you know i won't rate until i check the grade after i post the answer. I am tired of the people answering without knowledge or just by guessing
just to let you know i won't rate until i check the grade after i post the answer. I am tired of the people answering without knowledge or just by guessing
just to let you know i won't rate until i check the grade after i post the answer. I am tired of the people answering without knowledge or just by guessing
The Department of Transportation has found that a proposed highway project is not going to be completed before the end of the summer. They have asked the contractor to prepare cost figures to shorten the project by up to 4 weeks.
The following table shows the Crashing Costs for each activity. For example, if you needed to shorten Activity 1-2 by 1 week this would cost $12. If you needed to shorten the same activity by 2 weeks it would cost $16. Note: If an activity lists a cost of $---, then this activity cannot be any shorter.
Activity
FirstWeek
Second Week
Third Week
1-2
$12
$16
$ ---
2-5
6
8
10
5-7
7
8
11
7-11
7
11
---
11-13
4
8
10
1-3
12
14
19
3-8
5
---
---
8-11
12
13
14
3-9
14
16
16
9-12
8
8
10
12-13
7
11
---
1-4
10
14
18
4-6
12
14
18
6-10
11
12
---
10-12
14
15
---
Activity
FirstWeek
Second Week
Third Week
1-2
$12
$16
$ ---
2-5
6
8
10
5-7
7
8
11
7-11
7
11
---
11-13
4
8
10
1-3
12
14
19
3-8
5
---
---
8-11
12
13
14
3-9
14
16
16
9-12
8
8
10
12-13
7
11
---
1-4
10
14
18
4-6
12
14
18
6-10
11
12
---
10-12
14
15
---
5 10 13 10 12Explanation / Answer
We see that the critical path here is 1-->3-->8--->11--->13 with a duration of 41 weeks.
To reduce thw duration, we will start with an activity that is on critical path and also has the least crash cost.
The first activity to be crashed is 11--13 by one day.
Now, there are two critical paths, viz. 1-->3-->8--->11--->13 and 1-->3--->9--->12--->13 with a duration of 40 each. To reduce the cost, the next sequence of crashing will be
11--13 and 12--13 by one week each ( again the cost being lowest)
Now, the critical paths remain the same, so crashing the same activities by one more week will make the duration 38 weeks.
Still, the critical paths are the same. The activity to be crashed now, is 3--8 on path 1-->3-->8--->11--->13 and 9--12 on the path 1-->3--->9--->12--->13
Total activites crashed
11--13 for 3 days. ( cost 10)
12-13 for 2 days ( cost 11)
3--8 for 1 week (cost 5)
9-12 for 1 week ( Cost 8)
Total cost of crashing = 10+11+5+8 = 34
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