CompTIA Project+ (PK0-005)Project Management ConceptsHard

A project manager is developing a schedule for a construction project. Task X (Pour Foundation) has a duration of 5 days. Task Y (Erect Walls) cannot start until Task X is 100% complete. Task Z (Install Roof) cannot start until Task Y is 100% complete. What is the total float (slack) for Task Y if the project's critical path is 15 days and Task Y is on the critical path?

  1. A3 days
  2. B5 days
  3. CVariable, depending on other tasks
  4. D0 days
Show answer & explanation

Correct answer: D. 0 days

If a task is on the critical path, by definition, it has zero total float. Any delay in a critical path activity will directly delay the project's completion date.

Why the other options are wrong

  • A. Incorrect. This would imply Task Y is not on the critical path or has some buffer.
  • B. Incorrect. This would imply Task Y is not on the critical path or has significant buffer.
  • C. Incorrect. While float can be complex, for a critical path activity, it is always zero by definition.

Total Float (Slack)

The amount of time that a schedule activity can be delayed or extended from its early start date without delaying the project finish date or violating a schedule constraint.

  • Calculated as Late Finish - Early Finish (LF - EF) or Late Start - Early Start (LS - ES).
  • Critical path activities have zero total float.
  • Positive float indicates flexibility; negative float indicates a schedule problem.

Memory trick: Schedule terms help manage time: ES, EF, LS, LF, Float.

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