Need help with Q 4,5,6. B&W; Systems B &W; Systems design and distribute a varie
ID: 465666 • Letter: N
Question
Need help with Q 4,5,6.
B&W; Systems B &W; Systems design and distribute a variety of management software products through the Internet and retail outlets like Best Buy. The company is current considering the development of an Internet based forecasting system. This system is designed specifically for the new start-up and small business owner. The project manager, after consulting with the technical staff and reviewing historical efforts, has developed the task descriptions, time estimates and immediate predecessor (IP) relations. This information is reported in Table 1. The project manager plans to use existing software components during the development phase as a means of keeping project costs and overall timeframe within bounds. Nevertheless, multiple task time estimates were formulated due, in part, to the inherent uncertainties associated with software development. Table 1 - Project Description and Time Estimates (weeks) Most Likel Task Most Optimistic Description I.P Most Pessimistic Requirements Market Assessment Design Development Testing Revising Documentation Quality Assurance Pricing Production Distribution 16 10 B,E C,E F,G,H.I H B&W;'s management team has established a 35-week completion time for this effort. A preliminary assessment by the project management indicates that some of the project tasks will need to be shortened to meet the management deadline of 35 weeks. According, the project manager has prepared a set of task crashing estimates that are highlighted in Table 2. Table 2 - Project Crash Data Normal Costs (S) 10000 20000 15000 45000 10000 15000 20000 10000 5000 40000 15000 Crash Costs (S 10000 25000 30000 65000 20000 18000 30000 15000 5000 50000 25000 Task Crash Time (weeks)Explanation / Answer
Activity
Preceding activity
Optimistic time
Most Likely time
Pessimestic tie
Expected time
Variance
o
m
p
te =(o+4m+p)/6
*
A
-
2
3
4
3.00
0.1111
B
A
4
7
10
7.00
1.0000
C
A
5
6
9
6.33
0.4444
D
C
6
7
16
8.33
2.7778
E
D
7
9
10
8.83
0.2500
F
B,E
4
5
6
5.00
0.1111
G
D
3
6
10
6.17
1.3611
H
C, E
2
4
7
4.17
0.6944
I
B
2
2
2
2.00
0.0000
J
F, G, H, I
3
4
14
5.50
3.3611
K
J
2
3
4
3.00
0.1111
Activity
On Critical Path
Average Time
Earliest Start
Earliest Finish
Latest Start
Latest Finish
Total Slack
Activity Variance
Critical Path Variance
A
y
3.00
0.00
3.00
0.00
3.00
0.00
0.2500
0.2500
B
N
7.00
3.00
10.00
19.50
26.50
16.50
0.1111
C
y
6.33
3.00
9.33
3.00
9.33
0.00
0.6944
0.6944
D
y
8.33
9.33
17.67
9.33
17.67
0.00
0.1111
0.1111
E
y
8.83
17.67
26.50
17.67
26.50
0.00
0.2500
0.2500
F
y
5.00
26.50
31.50
26.50
31.50
0.00
0.1111
0.1111
G
N
6.17
17.67
23.83
25.33
31.50
7.67
1.0000
H
N
4.17
26.50
30.67
27.33
31.50
0.83
0.4444
I
N
2.00
10.00
12.00
29.50
31.50
19.50
0.2500
J
y
5.50
31.50
37.00
31.50
37.00
0.00
0.1111
0.1111
K
y
3.00
37.00
40.00
37.00
40.00
0.00
0.1111
0.1111
Length of Project
40.00
Project Varience
1.6389
Project S.D.
1.2802
Mean Length of Project
40
Critical Path
A-C-D-E-F-J-K
Activity
Duration
NC
CT
CC
Crashing duration
Crashing cost per week
A
3.0
10000
3
10000
0
0
B
7.0
20000
6
25000
1
5000
C
6.3
15000
5
30000
1
11250
D
8.3
45000
6
65000
2
8571
E
8.8
10000
8
20000
1
12000
F
5.0
15000
4
18000
1
3000
G
6.2
20000
4
30000
2
4615
H
4.2
10000
3
15000
1
4286
I
2.0
5000
2
5000
0
0
J
5.5
40000
5
50000
1
20000
K
3.0
15000
2
25000
1
10000
4.
For reducing the project duration to 35 weeks, the activities to crashed and their crashing cost are listed below:
Activity
On Critical Path
Average Time
Earliest Start
Earliest Finish
Latest Start
Latest Finish
Total Slack
A
y
3.00
0.00
3.00
0.00
3.00
0.00
B
n
7.00
3.00
10.00
16.66
23.66
13.66
C
y
5.33
3.00
8.33
3.00
8.33
0.00
D
y
6.33
8.33
14.66
8.33
14.66
0.00
E
y
8.83
14.66
23.49
14.66
23.49
0.00
F
n
4.00
23.49
27.49
23.66
27.66
0.17
G
n
6.17
14.66
20.83
21.50
27.66
6.84
H
y
4.17
23.49
27.66
23.49
27.66
0.00
I
n
2.00
10.00
12.00
25.66
27.66
15.66
J
y
5.50
27.66
33.16
27.66
33.16
0.00
K
y
2.00
33.16
35.16
33.16
35.16
0.00
Length of Project
35.16
Still the critical path is A-C-D-E-F-J-K
Activities to be crashed
Additional Cost
F by 1 week
3000
D by 2 weeks
20000
K by 1 week
10000
C by 1 week
15000
Total Additional cost = $48,000
5.
As the B is non-critical activity increase in the duration to 9 weeks does not change the critical path.
6.
If the duration of activity D is reduced to 7 weeks, than the crashing cost will reduce.
Activity
Preceding activity
Optimistic time
Most Likely time
Pessimestic tie
Expected time
Variance
o
m
p
te =(o+4m+p)/6
*
A
-
2
3
4
3.00
0.1111
B
A
4
7
10
7.00
1.0000
C
A
5
6
9
6.33
0.4444
D
C
6
7
16
8.33
2.7778
E
D
7
9
10
8.83
0.2500
F
B,E
4
5
6
5.00
0.1111
G
D
3
6
10
6.17
1.3611
H
C, E
2
4
7
4.17
0.6944
I
B
2
2
2
2.00
0.0000
J
F, G, H, I
3
4
14
5.50
3.3611
K
J
2
3
4
3.00
0.1111