PMI Project Management Professional Practice Question

The correct answer is 15 days. To calculate the Late Start (LS) for Activity X, we need to work backwards from the project completion date. Since the project must be completed in 20 days and Activity X has a duration of 5 days, the latest time it can start without delaying the project is 15 days after the project start. This allows the activity to finish exactly when the project needs to be completed (20 - 5 = 15). If Activity X started any later, it would push the project completion beyond the required 20 days. Understanding Late Start is crucial for project managers as it helps identify the flexibility in scheduling activities that are not on the critical path.