Critical Path Question
Ok, sorry for posting this hear but I don't have an instructor to ask. I just completed a PMI Study Hall practice question and the answer seems insane to me.
Question:
Find the critical path. All tasks are 3 days in length. There are two possible choices 6-9-10 and 6-7-8-9-10. Task 9 won't start until 10 days after the start of task 6. Therefore, tasks 6, 7 and 8 will be completed within the 10 day wait time.
I said 6-9-10, since tasks 7 and 8 have a day of float. Study Hall said the answer was 6-7-8-9-10. Also the explanation included this , "Option 6-9-10 and Option 6-3-4-5 both do not include task 9 which is on the critical path, i.e. if task 9 is delayed, the entire project is delayed. Hence they are not correct."
WTF?
Posted May 16, 2023, 2:57 PM UTC
This is because of the 10 days of waiting time between tasks 6 and 9. If you go the 6-9-10 route, you will have 7 days of float added between 6 and 9 because 9 has the constraint of not being able to start until 10 days after task 6 is started. In the critical path, you have to minimize float, so filling those 7 days with tasks 7 and 8 is the most efficient. Going 6-7-8-9-10 only adds 1 day of float, versus 6-9-10 adds 7 days. The explanation given seems off though, and I might be missing more context.