Question

The next set of questions use the following example:

A network consists of the activities in the following list. Times are given in weeks.

CAN ONLY BE ONE OF THE OPTIONS it's not 5 I tried that.

Activity	Preceding	Time
A	--	8
B	--	3
C	A	7
D	A,B	3
E	C	4
F	D	6

Draw the network diagram.

Calculate the ES, EF, LS, LF, and Slack for each activity.

Find the total project completion time.

What is the slack of activity B?

7

3

8

2

0

What is the LS of activity D?   

Week 8

Week 13

Week 10

Week 11

Week 7

Answer 1

Solution:

(a) From the given information, network diagram can be drawn as below:

(b) From the network diagram, the ES, EF, LS and LF for each activity is computed below:

ES - Early Start

EF - Early Finish

LS - Late Start

LF - Late Finish

Slack is calculated as:

Slack = (LS - ES) or (LF - EF)

The computed values of ES, EF, LS, LF and Slack are summarized in the table below:

(c) Project completion time is given by the EF i.e. Early Finish time of the last activity. Here, the EF of last activity E is 19. Therefore,

Total project completion time = 19 weeks

From the above table:

(1) Slack of activity B = 7 weeks

(2) LS of activity D = Week 10