examples of PERT Network

1. UNIT-II
NW ANALYSIS

2. Acti
vity
Prede
cessor
Completi
on time
A - 2
B - 9
C - 4
D A 5
E D 8
F E 3
G B 4
H G,I 11
I C 5
J C 7
K J 5
A
B G
F
E
D
I
J
C
H
K

4. • A project is represented by the network shown below and has the following data.
Determine (i) the critical path and, (ii) project completion time.
Task A B C D E F G H I
Optimistic
time (days)
4 18 26 16 15 6 8 7 3
Pessimistic
time
(days)
10 22 40 20 25 12 12 9 5
Most likely
time
(days)
7 20 33 18 20 9 10 8 4

5. Network modelling
• The time and cost estimates of different activities of a project and their precedence relationship
are ' given below: Overhead costs amount to Rs. 1,000 per week. It is stipulated that the contractor
will have to pay a penalty of Rs. 2,000 per week for completing the project beyond 16 weeks. i)
Show the critical path in the network Diagram.
• (ii) Find out the cost slope for every activity using normal and crash date for time and cost.
• (iii) Crash the project to 16 weeks, Estimate the total cost of crashing.
Activity Preceding
activity
Time (weeks) Cost (Rs.)
Normal Crash Normal Crash
A - 6 4 10,000 14,000
B - 4 3 5,000 8,000
C A 3 2 4,000 5,000
D B 8 3 1,000 6,000
E B 14 6 9,000 13,000
F C,D 8 4 7,000 8,000

6. There are seven activities in a project and the time estimates (weeks) are as follows
Activit
y
A B C D E F G
To 2 4 2 2 3 6 1
Tm 6 6 3 4 6 10 3
Tp 10 12 4 6 9 14 5
The logical sequence of activities is:
i. Activities A and B start at the beginning of the project.
ii. When A is completed C and D start.
iii. E can start when B and D are finished. Page 4 of 4
iv. F can start when B, C and D are completed.
v. E can start only when B and D are finished and is the final activity.
vi. G can start when F is finished and is final activity.
Draw the project network and find expected project completion time? And also calculate the
probability that the project will be completed at least 2 weeks earlier than expected.