CHAPTER 9 Managing Projects
1. Construct a network from the information in the following table and identify all the paths in the network, compute
the length of each, and indicate the critical path.
2. For the network in Problem 1, determine the earliest start and finish times, latest start and finish times, and slack
for each activity. Indicate how the critical path would be determined from this information.
3. The Farmer’s American Bank of Leesburg is planning to install a new computerized accounts system. Bank
management has determined the activities required to complete the project, the precedence relationships of the
activities, and activity time estimates as follows:
Determine the earliest and latest activity times, the expected completion time and standard deviation, and the
probability that the project will be completed in 40 weeks or less.
4. The following table provides the crash data for the project network in Problem 3. The normal activity times are
considered to be deterministic and not probabilistic.
Answers
1.
Paths: 2  5  7
2467
1 3  6  7
10  4  2  16
Activity
1
2
3
4
5
6
7
EF
7
10
13
15
14
18
20
10  5  3  2  20*
7  6  3  2  18
2.
Time
7
10
6
5
4
3
2
ES
0
0
7
10
10
15
18
Critical path activities have no slack.
Critical path  2-4-6-7  20
3.
LS
2
0
9
10
14
15
18
LF
9
10
15
15
18
18
20
Slack
2
0
2
0
4
0
0
4.
Project completion time  33
Normal cost  28800
Minimum project completion time  26
Crash cost  33,900
Normal
Crash
Normal
Time
Time
Cost
a
9
7
4,800
b
11
9
9,100
c
7
5
3,000
d
10
8
3,600
e
1
1
0
f
5
3
1,500
g
6
5
1,800
h
3
3
0
i
1
1
0
j
2
2
0
k
8
6
5,000
Critical path  a-d-g-k ,
Crashing cost  $5,100
Total network cost  $33,900
Crash
Cost
6,300
15,500
4,000
5,000
0
2,000
2,000
0
0
0
7,000
Normal
Cost
750
3,200
500
700
0
250
200
0
0
0
1,000
Crash
By
2
0
0
2
0
0
1
0
0
0
2
Crashing
Cost
1,500
0
0
1,400
0
0
200
0
0
0
2,000