You are the project manager for your organization. You have recorded the following duration
estimates for an activity in your project: optimistic 20, most likely 45, pessimistic 90. What time will
you record for this activity?

A.
48

B.
20o, 45m, 90p

C.
90

D.
45

Explanation:
This is an example of a three-point estimate. A three-point estimate records the optimistic, most
likely, and the pessimistic duration, and then records an average for the predicted duration Three-point estimate is a way to enhance the accuracy of activity duration estimates. This concept is

originated with the Program Evaluation and Review Technique (PERT). PERT charts the following
three estimates: Most likely (TM): The duration of activity based on realistic factors such as
resources assigned, interruptions, etc.
Optimistic (TO): The activity duration based on the best-case scenario
Pessimistic (TP): The activity duration based on the worst-case scenario
The expected (TE) activity duration is a weighted average of these three estimates:
TE = (TO + 4TM + TP) / 6
Duration estimates based on the above equations (sometimes simple average of the three
estimates is also used) provide more accuracy. It can be calculated as follows:
TE = ( 20 + 45*4 + 90) / 6
= 290/6
=48
Answer options B, C, and D are incorrect. These are not the valid answers for this question.