The Lockhead Aircraft Co. is ready to begin a project to develop a new fighter airplane for the U.S. Air Force. The company’s contract with the Department of Defense calls for project completion within 100 weeks, with penalties imposed for late delivery.

The project involves 10 activities (labeled A, B, . . . , J), where their precedence relationships are shown in the following project network.

T

(d) Now consider the other path through the project network.

Find the approximate probability that this path will be completed within 57 days.

(e) Since these paths do not overlap, a better estimate of the probability that the project will finish within 57 days can be obtained as follows. The project will finish within 57 days if both paths are completed within 57 days. Therefore, the approximate probability that the project will finish within 57 days is the product of the probabilities found in parts

(c) and (d). Perform this calculation. What does this answer say about the accuracy of the standard procedure used in part (c)?