Question

Sch.W Foundry, a metalwork plant in Quebec, has just decided to make a major investment in new air pollution control equipment. The plant, however, must be shut during this installation process. Sch.W’s board of directors estimates that the company can survive no more than 16 weeks without production in full swing. The managing partner wants to make sure the installation of the filtering system progresses smoothly and on time.

The activities involved in the foundry project are presented in the table below. Find the earliest start and finish, latest start and finish, and slack of each activity. Which activities are critical? Will the project finish in 16 weeks?

Activity	Description	Time Estimate (weeks)	Immediate Predecessor(s)
A	Building internal components	3	-
B	Modify roof and floor	4	-
C	Construct collection stack	3	A
D	Pour concrete and install frame	5	B
E	Build high-temperature burner	5	C
F	Install control system	3	C
G	Install air pollution device	5	D,E
H	Inspection and testing	3	F,G

Answer 1

Please refer the image uploaded.

ES = Early start, LS = Latest start , EF = Early Finish, LF = Latest Finish

Slack Formula = LS - ES

ES , EF , LS , LF , Slack (activity A) = 0 week, 3 weeks, 0 weeks , 3 weeks, 0 week (Critical activity as Slack = 0)

ES , EF , LS , LF , Slack (activity B) = 0 week, 4 weeks, 2 weeks , 6 weeks, 2 weeks

ES , EF , LS , LF , Slack (activity C) = 3 week, 6 weeks, 3 weeks , 6 weeks, 0 week (Critical activity as Slack = 0)

ES , EF , LS , LF , Slack (activity D) = 4 week, 9 weeks, 6 weeks , 11 weeks, 2 weeks

ES , EF , LS , LF , Slack (activity E) = 6 week, 11 weeks, 6 weeks , 11 weeks, 0 week (Critical activity as Slack = 0)

ES , EF , LS , LF , Slack (activity F) = 6 week, 9 weeks, 13 weeks , 16 weeks, 7 weeks

ES , EF , LS , LF , Slack (activity G) = 11 week, 16 weeks, 11 weeks , 16 weeks, 0 week (Critical activity as Slack = 0)

ES , EF , LS , LF , Slack (activity H) = 16 week, 19 weeks, 16 weeks , 19 weeks, 0 week (Critical activity as Slack = 0)

A - C - E - G - H (Critical path)

No, the project will not finish in 16 weeks but it will take 19 weeks to finish (Answer)