Her staff also has estimated the normal and crash times and costs for tasks invo
ID: 465539 • Letter: H
Question
Her staff also has estimated the normal and crash times and costs for tasks involved in the breakdown. The information is summarized below. The campaign starts on 4/1/2016.
Task
Time Estimates (Weeks)
Cost Estimates ($)
Normal
Crash
Normal
Crash
A1
6
4
5,000
10,000
B2
3
3
4,000
4,000
C
10
8
4,000
7,000
D
4
2
1,000
2,000
E
2
1
1,000
2,000
F
3
1
4,000
7,600
G
5
4
7,000
12,000
H
7
5
8,000
14,000
I
2
2
1,200
1,200
J
4
3
5,000
5,800
K
8
6
13,000
15,000
L
5
5
6,000
6,000
M
4
4
2,500
2,500
1 Task A can be crashed by 2 weeks at an additional cost of $5000 ($2,500/week).
2 Task B cannot be crashed.
Ann has to campaign for 35 weeks. Determine the total cost needed to complete the project with Ann’s time constraint.
Hint: Only the tasks in CP can be crashed to shorten the project duration. Consider the tasks with more days with less cost to crash.
Complete the attached answer sheet, save it as Your Name Assignment 10, and submit it with your MPP file in Assignment 10 area
Name:_______________
Answers:
Question 1.
Critical Path:
Duration:
Finish date:
Question 2
Total normal project cost:
$______________
Question 3
Tasks that should be crashed and additional cost:
Task
Weeks to cut
Cost
C.P. after crash
Question 4
Total crashed project cost:
$_____________
Question 5: Your MPP file
Task
Time Estimates (Weeks)
Cost Estimates ($)
Normal
Crash
Normal
Crash
A1
6
4
5,000
10,000
B2
3
3
4,000
4,000
C
10
8
4,000
7,000
D
4
2
1,000
2,000
E
2
1
1,000
2,000
F
3
1
4,000
7,600
G
5
4
7,000
12,000
H
7
5
8,000
14,000
I
2
2
1,200
1,200
J
4
3
5,000
5,800
K
8
6
13,000
15,000
L
5
5
6,000
6,000
M
4
4
2,500
2,500
Explanation / Answer
Step 1: Determine Critical Path
To determine critical path first identify the Earliest and Latest start and Finish times:
Task
Normal
ES
EF
LS
LF
Slack
Critical Activities
A
6
0
6
0
6
0
y
B
3
0
3
9
12
9
C
10
6
16
6
16
0
y
D
4
3
7
12
16
9
E
2
16
18
19
21
3
F
3
16
19
16
19
0
y
G
5
18
23
21
26
3
H
7
19
26
19
26
0
y
I
2
26
28
26
28
0
y
J
4
28
32
31
35
3
K
8
28
36
28
36
0
y
L
5
32
37
35
40
3
M
4
36
40
36
40
0
y
Project Completion (weeks)
40
The Project completion time = 40 weeks
Critical path: Activities for which slack = LF – EF is zero are critical activities, and the path formed by this activities in critical path.
Critical path is A-C-F-H-I-K-M, duration of critical path is 40 weeks.
Total cost of project without crashing = $61,700.
Crashing of Project
For crashing first determine Allowable crashing weeks and crashing cost per week.
Allowable Crashing = Normal Time – Crash Time
Crashing Cost per week = (Crash Cost – Normal Cost)/Allowable crashing.
Time Estimates (Weeks)
Cost Estimates ($)
Allowable crashing weeks
Crashing cost per week
Task
Normal
Crash
Normal
Crash
A
6
4
5,000
10,000
2
2500
B
3
3
4,000
4,000
0
0
C
10
8
4,000
7,000
2
1500
D
4
2
1,000
2,000
2
500
E
2
1
1,000
2,000
1
1000
F
3
1
4,000
7,600
2
1800
G
5
4
7,000
12,000
1
5000
H
7
5
8,000
14,000
2
3000
I
2
2
1,200
1,200
0
0
J
4
3
5,000
5,800
1
800
K
8
6
13,000
15,000
2
1000
L
5
5
6,000
6,000
0
0
M
4
4
2,500
2,500
0
0
Total Normal Cost
$61,700
For crashing, only critical activities are considered for reduction in completion period.
From the critical activities least crashing cost per week is for critical activity K, that is $1000 per week and allowable reduction is by 2 weeks.
By crashing the activity K to 6 weeks, the critical path is same, A-C-F-H-I-K-M with new path duration of 38 weeks.
From the critical activities least crashing cost per week is for critical activity C, that is $1500 and allowable reduction is by 2 weeks.
By crashing the activity C to 8 weeks, the critical path is same, A-C-F-H-I-K-M with new path duration of 36 weeks.
From the critical activities least crashing cost per week is for critical activity F, that is $1800 and allowable reduction is by 2 weeks.
By crashing the activity F to 2 weeks, the critical path is same, A-C-F-H-I-K-M with new path duration of 35 weeks.
Thus, after crashing the activities K, C and F the project completion time is 35 weeks which is desired completion time by Ann. So stop crashing ahead.
The crashing is reviesed in the earliest and Latest time calculation as follows:
Task
Normal
ES
EF
LS
LF
Slack
Critical Activities
A
6
0
6
0
6
0
y
B
3
0
3
7
10
7
C
8
6
14
6
14
0
y
D
4
3
7
10
14
7
E
2
14
16
16
18
2
F
2
14
16
14
16
0
y
G
5
16
21
18
23
2
H
7
16
23
16
23
0
y
I
2
23
25
23
25
0
y
J
4
25
29
26
30
1
K
6
25
31
25
31
0
y
L
5
29
34
30
35
1
M
4
31
35
31
35
0
y
Project Completion time
35
Answers:
Question 1.
Critical Path:
A-C-F-H-I-K-M
Duration:
40 weeks
Finish date:
40 weeks
Question 2
Total normal project cost:
$61,700
Question 3
Tasks that should be crashed and additional cost:
Task
Weeks to cut
Cost
C.P. after crash
K
2
1000 x 2 = 2000
A-C-F-H-I-K-M
C
2
1500 x 2 = 3000
A-C-F-H-I-K-M
F
1
1800 x 1 = 1800
A-C-F-H-I-K-M
Question 4
Total crashed project cost:
$ 61,700 + $2000 + $3000 + $1800 = $68,500
Task
Normal
ES
EF
LS
LF
Slack
Critical Activities
A
6
0
6
0
6
0
y
B
3
0
3
9
12
9
C
10
6
16
6
16
0
y
D
4
3
7
12
16
9
E
2
16
18
19
21
3
F
3
16
19
16
19
0
y
G
5
18
23
21
26
3
H
7
19
26
19
26
0
y
I
2
26
28
26
28
0
y
J
4
28
32
31
35
3
K
8
28
36
28
36
0
y
L
5
32
37
35
40
3
M
4
36
40
36
40
0
y
Project Completion (weeks)
40
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