Question

(UPDATED) Consider a project that requires the completion of 7 tasks, as follows:

o Tasks A and B can begin simultaneously at the beginning (“time zero”).

o Task C can only begin after task B is completed.

o Task D can only begin after task A is completed.

o Task E can only begin after task A is completed.

o Task F can only begin after task E is completed.

o Task G can only begin after tasks C and D are completed.

The expected durations (in days) of each task are as follows: A=15; B=20; C=10; D=10; E=30; F=20; G=40.

What is the expected completion of the whole project?

A. 50 days

B. 60 days

C. 70 days

D. 75 days

Consider the project from the previous question with the added complexity that the actual completion time of each task will be:

Task	Completion Time
A	15+RANDBETWEEN(-8,8)
B	20+RANDBETWEEN(-8,8)
C	10+RANDBETWEEN(-8,8)
D	10+RANDBETWEEN(-8,8)
E	30+RANDBETWEEN(-8,8)
F	20+RANDBETWEEN(-8,8)
G	40+RANDBETWEEN(-8,8)

Using PERT, what is the expected completion time of the project?

A. 50 days

B. 60 days

C. 70 days

D. 75 days

Answer 1

First, prepare a chart with the expected duration and precedence order.

Based on this, the duration time is 70 days.

Part 1 : Option C (70 days)

Part 2

This will be based on the estimated task times which include a randbetween function as well. This will lead to different overall estimated time since every time we run the function on excel, a different value will be returned.

Below is a the table based on the values returned when I ran the randbetween function.

Based on this, the value of the expected completion time is 58 days which can be approximated to 60 days (Option B)