Mechanical Engineering - Industrial Engineering and Production Management - Discussion

Slack = Earliest finish time - latest allowable time.

In this case, a negative value means the latest allowable time is more. So it shows option A is right.

Slack is the amount of time that an activity can be delayed past its earliest start or earliest finish without delaying the project. The critical path is the path through the project network in which none of the activities have slack, that is, the path for which ES=LS and EF=LF for all activities in the path.

At, critical activity, Float or Slack is Zero.

Negative Slack is behind Schedule and
Positive Slack is Ahead of Schedule.

Hence Option B.

If total slack is a positive number, it indicates the amount of time that the task can be delayed without delaying the project finish date. If total slack is a negative number, it indicates the amount of time that must be saved so that the project finish date is not delayed.

Negative slack indicates that there is not enough time scheduled for the task and is usually caused by constraint dates.

By default and by definition, a task with 0 slack is considered a critical task. If a critical task is delayed, the project finish date is also delayed.

Its. Answer is C that the critical activity leads to -ve slack.

Slack or float is time by which any activity delay without delaying project completion.

Positive slack-----ahead of schedule.

Negative slack------behind the schedule.

Zero slack ---------on the schedule.