Question On Slack

can anyone help clarify the following question please?

The project is two weeks ahead of schedule with three team members working on it. Two of these team members are working on the critical path-related items. What is the slack of the critical path?

A) Negative two weeks

B) Plus two weeks

C) 0 (Zero)

D) Not enough information

The answer given is B) Plus two weeks

I thought the answer should be c) 0 (zero)

The question is asking what is the slack of the critical path. Slack and float are the same thing and I thought that the critical path does not have slack/float. 

Can someone can please kindly help clarify this for me? Thank you 

Answer is B Plus 2 weeks.

1. The project is on schedule means the duration of the project equal to the critical path duration.  Hence the Float/Slack of the critical path activities is equal to Zero.

2. Whereas, if the schedule is 2 weeks behind the schedule means the float/slack of the activities in the critical path is also 2 weeks behind(-2 weeks or -14days).

if you need to critical path activities float/slack equals to zero means we need to recover  +2weeks/+14 days to the schedule.  so, compress (Fast Track/Crash) the schedule to recover 2 weeks then the project will complete on schedule. That means earlier Float -2 weeks + 2 weeks recover float equals to zero. 

3. Therefore, the Project is two weeks ahead of schedle  means the float of the activities in the critical path is 2 weeks ahead i.e. Plus 2 weeks( 14 days float/slack).




I think it is negative two weeks slack. If you are ahead of the schedule, then, it would be counted as a negative. - Paul Savramis