Dave Fletcher was able to determine the activity times for constructing his lase
ID: 3142420 • 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:
Dave's earliest start (ES) and earliest finish (EF) are:
Activity
ES
EF
A
____
5
B
0
_____
C
_____
7
D
5
_____
E
_____
11
F
8
_____
G
_____
20
H
_____
22
Dave's latest start (LS) and latest finish (LF) are:
Activity
LS
LF
H
14
_____
G
13
_____
F
8
_____
E
10
_____
D
13
_____
C
11
_____
B
0
_____
A
6
_____
The slack times are:
Activity
Slack
A
_____
B
_____
C
_____
D
_____
E
_____
F
_____
G
_____
H
_____
The activities on the critical path are _____ - _____ - _____ - _____
The total project completion time for Dave =_____ weeks.
Activity
ES
EF
A
____
5
B
0
_____
C
_____
7
D
5
_____
E
_____
11
F
8
_____
G
_____
20
H
_____
22
Explanation / Answer
Activity times are not given in the problem.
So let us assume the activity times as follows
A: tA
B: tB
C:tC
D:tD
E: tE
F: tF
G:tG
H:tH
The formulae for the ES & EF calculation is given below
ES of an activity = EF of that activity - time duration of that activity
EF of an activity = ES of that activity + time duration of that activity
Henc, for the given problem, it is as follows
(Use actual values of the activity times tA,tB , ......for calculation)
Computation of Latest Start(LS) and latest finish(LF) of activities
LF of an activity = LS of that + time duration of that activity.
SLACK of an activity = LS of the activity - ES of the activity
Activities with 0 slack values are considered as critical activities.
Total project completion time is obtained by summing up the activity times of critical activities.
Activity ES EF A 5- tA 5 B 0 0+tB C 7-tC 7 D 5 5+tD E 11-tE 11 F 8 8+tF G 20-tG 20 H 22-tH 22Related Questions
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