Question

Hi, Please draw the network diagram.

Activity D on a CPM network has predecessors B and C, and has successor F. D has duration 6. B's earliest finish is 18, while C's is 20. F's late start is 26. Which of the following is definitely true?

A) B is a critical activity.

B) C is completed before B.

C) D has no slack but is not critical.

D) D is critical, and has zero slack.

E) F is critical, and has zero slack.

Answer: D

Answer 1

Answer: E) F is critical and has zero slack.

Explanation: Network diagram

Given

Activity	Duration	Early start=Max of early finish of last activities	Early finish = early start + duration	Late finish= Min of late start of after activities	Late start= late finish - duration	Total slack= late finish – early start	Critical activity, activities with 0 slack time
B			18
C			20
D	6
F					26

Solving by steps

Activity	Duration	Early start=Max of early finish of last activities	Early finish = early start + duration	Late finish= Min of late start of after activities	Late start= late finish - duration	Total slack= late start – early start	Critical activity, activities with 0 slack time
B			18
C			20
D	6	1st- 20	2nd- 26
F		3rd- 26			26	4th- 0	5th- yes

F is critical activity and has 0 slack