PERT uses the formula of (O+4M+P)/6 to predict the duration of the project activities and the overall

project schedule.

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.

Answer option A is incorrect. This is not a valid formula.

Answer option D is incorrect. This almost describes the three-point estimate, but does not answer

the question about PERT.

Answer option B is incorrect. This is the formula for the three-point estimate. Note the PERT, while

similar, uses 4M and divides the result by

six factors.