Dave Fletcher was able to determine the activity times for constructing his lase
ID: 387273 • Letter: D
Question
Dave Fletcher was able to determine the activity times for constructing his laser scanning machine. Fletcher would like to determine ES, EF, LS, LF, and slack for each activity. The total project completion time and the critical path should also be determined. Here are the activity times:
1. Dave's earliest start (ES) and earliest finish (EF) are:
2. Dave's latest start (LS) and latest finish (LF) are:
3. The slack times are:
4. The activities on the critical path are
5. The total project completion time for Dave = ? weeks
activity time(weeks) immediate predecessor activity time(weeks) immediate predecessor A 7 -- E 3 B B 8 -- F 7 B C 2 A G 11 C,E D 2 A H 6 D, FExplanation / Answer
From the precedence relationship, the possible paths and their corresponding durations as follows :
A-C-G = 7 + 2 + 11 = 20 weeks
B-E-G = 8 + 3 + 11 = 22 weeks
A-D-H = 7 + 2 + 6 = 15 weeks
B-F-H = 8 +7 + 6 = 21 weeks
4)Out of above, B-E-G is the critical path by virtue of having the longest duration
Activities on critical path are B, F, H
5) Project completion time will be same as duration of critical path. Therefore, project completion time will be 22 weeks
3)It is to be noted that Slack time of all activities lying on critical path are ZERO.
Therefore , slack time of activities B, E,G are ZERO
Slack time of activities F, H = Duration BEG – Duration BFH = 22 – 21 = 1 week
Slack time of activity A, C = Duration BEG – Duration ACG = 22 – 20 = 2 weeks
Slack time of activity D =Duration B-E-G – Duration ADH =21 – 15 = 6 weeks
Answer to questions 1 and 2 :
It is to be noted that :
Slack = Earliest Finish ( EF ) – Earliest Slack ( ES ) = Latest Finish ( LF ) - Latest slack ( LS )
Following table presents data on ES, EF, LS and LF
Activity
ES
LS
EF
LF
Slack
A
0
2
7
9
2
B
0
0
8
8
0
C
7
9
9
11
2
D
7
13
9
15
6
E
8
8
11
11
0
F
8
9
15
16
1
G
11
11
22
22
0
H
15
16
21
22
1
Activities on critical path are B, F, H
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.