PMP® Challenge Question - 1/1

For the first reader to successfully email a correct response to two of three challenge questions (12/15, 1/1, and 1/15), I have the following gift:

Emotional Intelligence for Project Managers – The People Skills You Need to Achieve Outstanding Results by Anthony Mersino, PMP.

So without further ado, here is the question:

What does PERT stand for? What company is usually credited with the "invention" of PERT? What is the basic PERT formula?

Good luck and have a Happy, Healthy, and Prosperous New Year!