CSLB General Building (B)Planning and EstimatingHard
On a CPM schedule, the critical path through the project totals 20 days. A parallel sequence of activities (Path B) that must also be completed totals 15 days. What is the total float available for Path B?
- A15 days
- B20 days
- C0 days
- D5 days
Show answer & explanationAnswer & explanation
Correct answer: D. 5 days
Float is the amount of time an activity or path can be delayed without affecting the project's overall completion date. Since the critical path is 20 days and Path B only requires 15 days, Path B has 20 - 15 = 5 days of float before it becomes critical.
Why the other options are wrong
- A. This is Path B's duration, not its float.
- B. This is the critical path duration, not the float value.
- C. Zero float describes the critical path itself, not Path B.
CPM Float Calculation
Float is the scheduling slack for a non-critical path, calculated as the difference between the critical path duration and that path's own duration.
- Critical path activities have zero float
- Float = critical path duration minus path duration
- Using up float on a path can make it become critical
Memory trick: The critical path has no slack; everything else has some.