1. The problem statement, all variables and given/known data A small purse manufacturer has a single machine that makes the metal parts of a purse. This takes 2 minutes. Another single machine makes the cloth parts in 3 minutes. Then it takes a worker 4 minutes to sew the cloth and metal parts together. How long will it take to make 6 purses? 2. Relevant equations The solution in the back of the book states that it will take 4.5 minutes to make each purse but I have no idea how they got this value. So, it will obviously take 6 x 4.5 = 27 minutes to make 6 purses. How did they get a time of 4.5 minutes? 3. The attempt at a solution Task Time Preceding Task A | 2 | None B | 3 | None C | 4 | A, B The following is incorrect but it is my attempt at solving the problem. A to C = 2 + 4 = 6 B to C = 3 + 4 = 7 So, B to C is the critical path which yields a time of 7 minutes. 6 x 7 = 42 So, it would take 42 minutes to make six purses.