PMI-SP Critical Path Method 4 — Questions and Answers
Question 1: A project scheduler is analyzing a network and finds that Activity X has Free Float of 0 but Total Float of 5 days. What does this mean?
- Activity X is on the critical path
- Delaying Activity X will delay its immediate successor
- Delaying Activity X will not delay its successor but could delay the project (Correct answer)
- Activity X has no scheduling flexibility at all
Correct answer: Delaying Activity X will not delay its successor but could delay the project
Zero free float means any delay impacts the next activity, but positive total float means the project end date is not immediately threatened.
Question 2: When using CPM, which output is MOST useful for identifying where to apply schedule compression effort?
- Resource histogram
- Network diagram with float values (Correct answer)
- Work Breakdown Structure
- Risk register
Correct answer: Network diagram with float values
A network diagram displaying float values clearly shows which activities are on the critical path (zero float) and where compression will shorten the schedule.
Question 3: In Activity-on-Node (AON) notation, which of the following represents a dependency relationship?
- A box containing activity information
- An arrow connecting two activity boxes (Correct answer)
- A diamond symbol at decision points
- A circle representing a network event
Correct answer: An arrow connecting two activity boxes
In AON (Precedence Diagramming Method), boxes represent activities and arrows between boxes represent logical dependencies.
Question 4: A project has a planned duration of 90 days. After crashing two critical path activities, the duration drops to 82 days at a cost of $4,000. What is the crash cost per day?
- $400
- $500 (Correct answer)
- $800
- $1,000
Correct answer: $500
Crash cost per day = Total crash cost ÷ Days saved = $4,000 ÷ 8 = $500 per day.
Question 5: Which statement best describes 'float consumption' during project execution?
- Float increases as activities are completed early
- Actual delays on non-critical activities reduce available float (Correct answer)
- Float is recalculated only at project milestones
- Float consumption only affects the critical path
Correct answer: Actual delays on non-critical activities reduce available float
As non-critical activities experience delays, their float is consumed, potentially making them critical or creating negative float.
Question 6: A project scheduler is told to 'level resources' on the schedule. How does resource leveling typically affect the critical path?
- It always shortens the critical path
- It has no effect on the critical path
- It may extend the critical path due to resource constraints (Correct answer)
- It eliminates float from all non-critical activities
Correct answer: It may extend the critical path due to resource constraints
Resource leveling resolves over-allocations by delaying activities, which can lengthen the critical path and extend the project end date.
Question 7: Which CPM concept describes the longest path through the network when considering both duration and imposed constraints?
- Total slack path
- Critical path (Correct answer)
- Resource-constrained critical path
- Constraint-driven path
Correct answer: Critical path
The critical path remains the longest path through the network; imposed date constraints can create negative float but do not change this definition.
PMI-SP Critical Path Method 4
A project scheduler is analyzing a network and finds that Activity X has Free Float of 0 but Total Float of 5 days.
What does this mean?