Question: Sager Products has been in the business of manufacturing and marketing toys for toddlers for the past two decades. Jim Sager, president of the firm, is considering the development of a new manufacturing line to allow it to produce high-quality plastic toys at reasonable prices. The development process is long and complex. Jim estimates that there are five phases involved and multiple activities for each phase. Phase 1 of the development process involves the completion of four activities. These activities have no immediate predecessors. Activity A has an optimistic completion time of 2 weeks, a most likely completion time of 3 weeks, and a pessimistic Phase 4 involves five activities. Activity Q requires activity K to be completed before it can be started. All three time estimates for activity Q are 6 weeks. Activity R requires that both activity L and activity M be completed first. The three time estimates for activity R are 1, 2, and 3 weeks. Activity S requires activity N to be completed first. Its time estimates are 6, 6, and 9 weeks. Activity T requires that activity O be completed. The time estimates for activity T are 3, 4, and 5 weeks. The final activity for phase 4 is activity U. The time estimates for this activity are 1, 2, and 3 weeks. Activity P must be completed before activity U can be started. Phase 5 is the final phase of the development project. It consists of only two activities. Activity V requires that activity Q and activity R be completed before it can be started. Time estimates for this activity are 9, 10, and 11 weeks. Activity W is the final activity of the process. It requires three activities to be completed before it can be started: activities S, T, and U. The estimated completion times for activity W are 2, 3, and 7 weeks.
(a) Given this information, determine the expected completion time for the entire process. Also determine which activities are along the critical path.
(b) Jim hopes that the total project will take less than 40 weeks. Is this likely to occur?
(c) Jim has just determined that activities D and I have already been completed and that they do not need to be part of the project. What is the impact of this change on the project completion time and the critical path?