Question

The following information has been gathered for a project to install a new machine lathe at Diamond Manufacturing, Inc.

Activity	Activity Time (wks)	Immediate Predecessor(s)
A	4	—
B	7	A
C	9	B
D	3	B
E	14	D
F	10	C, D
G	11	F, E

1. Draw the network diagram.
2. Calculate the slack for each activity and determine the critical path. How long will the project take?

Answer 1

Part a:

Part b.

To determine the critical path of the network following forward pass and backward pass schedule is developed:

		Forward Pass Schedule to determine Earliest times of activity	Backward Pass Schedule to determine latest times of activity
Activity	Activity time	Early Start	Early Finish	Late Start	Late Finish	Slack
	ti	ES = max(EF of preceding activities)	EF = ES + ti	LS = LF – ti	LF = min (LS of succeeding activities)	S = (LF – EF) Or S = (LS – ES)

The EF of the ending activity (F) = LF of the ending activity (F) = Completion time of the project = 41

The activity with slack = 0, are critical activities, and path formed by the these activities is known as critical path.

Critical activities are - A, B,C,F,G

Critical path:  A - B - C - F - G

Project completion time = 41 weeks