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Crashing question

Posted: Tue Feb 17, 2015 10:13 pm
by coolpmp69
5 tasks have to be completed one after another in your project. The contract with sponsor contains very strict penalties for project delay. The schedule reveals that the project has a negative float of 3 months. Which of the following task(s) should be crashed to bring the project on schedule? Refer to the table in the attachment

Options:
1. Task Q
2. Task N and Task O together
3. Either Task Q or Task N and Task O together
4. Task P and Task N together
------------------------

My take on this question : I compared the crash cost and months saved
The crashing costs and months saved for the given options are :
1. task q = $ 2650 ; 3 months saved
2. task N and task O together= $3950 ; 3 months saved
3. Either Task Q or Task N and Task O together = $2650/$3950 ; 3 months saved
4. Task P and Task N together = $5100 ; 3 months saved

All the above options save 3 months which is good to eliminate negative float. Thus based on the cost the option 1 Task Q should be crashed.

Experts opinion needed here.

Re: Crashing question

Posted: Wed Feb 18, 2015 10:57 am
by signor_rk
Let us calculate the additional cost required (= Crash Cost - Original Cost) to recover the negative float of 3 (three) months by CRASHING.

Options:
1. Task Q => $ 150
2. Task N and Task O together => ($100 + $50) = $150
3. Either Task Q or Task N and Task O together => $150 each
4. Task P and Task N together => ($200 + $100) = $300

Now , the Options # 1 , 2 & 3 are correct , but Option # 3 gives us the BEST choice as we find 2(two) options for selection.

Therefore , the Correct answer Option is Option # 3. Either Task Q or Task N and Task O together

Re: Crashing question

Posted: Wed Feb 18, 2015 1:48 pm
by coolpmp69
Ranjit, Agree with your additional cost calculation but if you see the crashing cost for option 3 it is either $2650 or $3950 (based on my calculation) then why would one pick option 3 than option1?
Based on PMBOK glossary : "Crashing is a technique used to shorten the schedule duration for the least incremental cost by adding resources"
so I still think option 1 is the best one.

Re: Crashing question

Posted: Fri Feb 20, 2015 1:55 pm
by coolpmp69
Any additional thought on this question?

Re: Crashing question

Posted: Sun Feb 22, 2015 2:49 am
by saket
I feel we should not spend too much time in eliminating options in such questions, we should understand how to calculate the crash cost, and in exam i do not expect we get same crash cost in more than one options. If that happen we need some additional information like risk etc to judge which one should be picked.