Question

A project manager, in preparation for the construction of roads, has identified the activities and their durations to prepare a difficult stretch of motorway (as in the following table).

Activity	Duration (days)	Preceding activities
A	5	-
B	10	-
C	1	-
D	8	B
E	10	B
F	9	B
G	3	A,D
H	7	A,D
J	3	F
K	8	E,H
L	4	C,J

(a) How long the project will take?

(b) State the critical activities.

(c) If activity A is delayed for 10 days, what is the effect on the project duration?

Answer 1

a)

AON:

Path and Duration are:

AG = 5+3 = 8

AHK = 5+7+8 = 20

BDG = 10+8+3 = 21

BDHK = 10+8+7+8 = 33

BEK = 10+10+8 = 28

BFJL = 10+9+3+4 = 26

CL = 1+4 = 5

The project time will be equal to highest time taken by a path which is 33 days

b)

Critical activities are those which are in critical path. Critical path is one with the highest time

Hence, critical activities are B,D,H,K

c)

Activity A is part of two path AG and AHK with time of 8 and 20 days respectively. Even if A is delayed by 10 days, the time for these path will change to 18 and 30 days. However, it is still less than time of critical path. So, it will have no effect on the project duration