SALLY’s Electric Co. in Princeton installs electrical fixtures at Princeton dormitories. Sally has been very concerned with the amount of time (Weeks) that it takes to complete electric wiring jobs. Some of her workers are very unreliable. A list of activities and their possible time is given in the following table (a: optimistic time; m: most likely time; b: pessimistic time)
Activity a m b predecessor(s)
A 4 6 8 -
B 2 3 4 -
C 1 2 3 -
D 6 7 8 C
E 2 4 6 B , D
F 6 10 14 A , E
G 2 3 4 A , E
H 7 8 9 F
I 3 6 9 F
J 5 6 7 G , H
K 6 7 8 C
L 6 8 10 I , J
1: Draw the appropriate PERT diagram.
2: Show ES, EF, LS, LF, and Slack time in the diagram above.
3: Identify the critical path and total completion time required to complete this project..
4: Determine the probability that SALLY will complete the project
(1) in 43 weeks or less, (2) more than 48 weeks, and (3) between 46 and 48 weeks.