TOPIC: CPM Float questions

Hi All,

www.oliverlehmann.com/pmp-self-test/75-free-questions.htm

Im pretty confused with the questions of 18 & 31 related with Float & free float.
My selection was wrong for both the questions.
Can someone guide me on this.

Thanks.

Regards,
Narayan

Q-31:

20
+8
+9=37


Please note that critical path(minimum total duration) is Activity 1-- Activity 3-- Activity 4

Activity 1 will take 10 days to complete
Activity 3 will be finished on 8 day after start of Activity 2. It has F to F relationship with lead of 2 days,so it can start anytime but can only finish on 10-2 i.e 8th day.

So as of now,we have duration of CP =28

Activity 4 will be finished on 37th day. 6 days + lag of 3 days =9

Sp CP duration= 28+9 = 37

Hope it clarifies.

Q-10:
Check the formulas for free float and total float and relate it to days.

Total float= Late Start date – Early Start date or Late Finish date – Early Finish date

If you choose to start your project from day 1
Free Float= ES of next Activity – EF of current Activity - 1( Free FLoat=9 , 22,23,24,25,26,27,28,29,30)

Make sure you first understand the difference in free float and total float.

I found this to be helpful: pmstudycircle.com/2013/03/total-float-versus-free-float/

A quick google search on "float vs free float" will give you a lot of other resources.