PMI-SP Critical Path Method 5 — Questions and Answers
Question 1: When compressing a schedule using crashing, which activities should be crashed first?
- Activities with the most float
- Critical path activities with the lowest crash cost per day (Correct answer)
- Non-critical activities to free up resources
- Activities with the longest duration regardless of path
Correct answer: Critical path activities with the lowest crash cost per day
To minimize cost while compressing the schedule, crash critical path activities starting with those that have the lowest crash cost per day.
Question 2: A Finish-to-Finish dependency requires that the successor activity finishes no earlier than how many days after the predecessor's finish (with a 4-day lag)?
- 4 days before the predecessor finishes
- At the same time as the predecessor
- 4 days after the predecessor finishes (Correct answer)
- 4 days after the predecessor starts
Correct answer: 4 days after the predecessor finishes
A Finish-to-Finish relationship with a 4-day lag means the successor cannot finish until 4 days after the predecessor finishes.
Question 3: Which of the following is a limitation of the Critical Path Method?
- CPM cannot handle Finish-to-Start relationships
- CPM assumes unlimited resources are available (Correct answer)
- CPM is only applicable to projects with fewer than 50 activities
- CPM cannot identify the longest path through a network
Correct answer: CPM assumes unlimited resources are available
Traditional CPM assumes resources are unlimited and always available, which rarely reflects real-world project conditions.
Question 4: During schedule analysis, a project manager identifies that the critical path has changed after a status update. What is the MOST likely cause?
- Scope was reduced on a critical activity
- A non-critical activity was delayed beyond its total float (Correct answer)
- Resource leveling was completed successfully
- A new risk was added to the risk register
Correct answer: A non-critical activity was delayed beyond its total float
When a non-critical activity is delayed beyond its total float, it becomes critical and may create a new, longer critical path.
Question 5: In CPM scheduling, a 'dummy activity' in an AOA network is used to:
- Represent summary activities in the WBS
- Show logical dependencies without consuming time or resources (Correct answer)
- Indicate a milestone with zero duration
- Mark the interface between project phases
Correct answer: Show logical dependencies without consuming time or resources
Dummy activities in AOA diagrams are zero-duration, zero-resource arrows that represent required logical dependencies between activities.
Question 6: A project network has activities with the following total floats: A=0, B=3, C=0, D=7, E=0. Which activities form the critical path?
- A, B, and C
- A, C, and E (Correct answer)
- B and D
- All activities with positive float
Correct answer: A, C, and E
Activities with zero total float (A, C, E) form the critical path; any delay in these activities directly delays the project.
Question 7: When a project manager applies a 'Start-to-Start with lead' relationship, what scheduling benefit is achieved?
- The successor is forced to wait longer before beginning
- Activities can overlap, reducing overall project duration (Correct answer)
- Resource conflicts are automatically resolved
- The predecessor's duration is shortened
Correct answer: Activities can overlap, reducing overall project duration
Start-to-Start with lead allows the successor to begin before the predecessor completes, enabling parallelism that can compress the schedule.
PMI-SP Critical Path Method 5
When compressing a schedule using crashing, which activities should be crashed first?