The Mohawk Discount Store chain is designing a management-training program for individuals at its corporate headquarters. The company would like to design the program so that the trainees can complete it as quickly as possible. There are important precedence relationships that must be maintained between assignments or activities in the program. For example, a trainee cannot serve as an assistant store manager until after she or he has had experience in the credit department and at least one sales department. The data below show the activity assignments that must be completed by each trainee