Calculation questions

Submitted by s_sunny123 on Mon, 08/17/2009 - 12:18

Hi friends,

 I was going through the Oliver Lehmann questions and got stuck on couple of questions. Need your help in solving the same as I have the correct answers, but dont know how did we arrive at that.

Q1. A project manager made 3-point estimates on a critical path and found the following results:

                opti         ML         Pessi      PERT weighted average     

 Act A        12           15          24                16.0

Act B         8             9           14                  9.7

Act C         15            19          27                19.7

Act D         10            14          28                15.7

Act E         17            20          35                 22.0

Assuming ±3 Sigma precision level for each estimate, what is the standard deviation of the allover path?

a. App. 4.2 days

b. App. 5.2 days (Right answer)

c. App. 6.2 days

d. You can not derive the path SD from the information given.

Q2. A company has to make a choice between two projects, because the available resources in money and kind are not sufficient to run both at the same time. Each project would take 9 months and would cost $250,000.

  1. The first project is a process optimization which would result in a cost reduction of $120,000 per year. This benefit would be achieved immediately after the end of the project.

     
  2. The second project would be the development of a new product which could produce the following net profits after the end of the project:

     Assumed is a discount rate of 5% per year. Looking at the present values of the benefits of these projects in the first 3 years, what is true?

 

1. year:       $ 15,000
2. year: $ 125,000
3. year: $ 220,000

a. Both projects are equally attractive.
b.  The first project is more attractive by app. 7%.
c. The second project is more attractive by app. 5%.
d. The first project is more attractive by app. 3%.---Right answer

 

Q3.

  A project manager needs a certain number of identical valve housings for a power station project.

He starts with 100 raw items which are made as metal castings. Out of this batch, 15 are found leaking from micro-porosities in a subsequent pressure test. 6 of these housings can be recovered by a special sealing process for raw castings.

The 91 housings are then being machined. After this process step 10 machined castings are found leaking. 3 of these items can also be saved using another sealing process for machined castings.

The remaining 84 housings are getting mounted to the power plant pipe work. During a pressure test after this process step it is found that 12 valves are leaking. Out of these a number of 6 valves can be saved by replacing the sealing rings used.

Finally the project manager has 78 valves which he can use. What is true?
 

RTY = 0.84

RTY = 0.78
RTY = 0.91
RTY = 0.65----Right answer

Q4. Activity 1 has a duration of 20 days, Activity 2 of 10 days, Activity 3 of 5 days and Activity 4 of 6 days.

What is the minimum total duration between the Milestones A and B?
a. 36 days

b. 37 days ---Right answer

c. 39 days

d. 42 days

It would be great if someone can help me in understanding the calculations for above questions.

 Thanks in advance

Zuzu

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Goose

Tue, 08/18/2009 - 03:41

Hi s_sunny -    I took the exam on August 12th and passed.  I just want to be honest and say there was nothing even remotely like any of these questions on the exam.  I also looked at Oliver's website/questions and glad I did not spend much time at all on the material.   The questions on the exam were very straightforward...much like what is in the back of the Andy Crowe book.

 Just my opinion.   Good luck !

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admin

Tue, 08/18/2009 - 05:10

I would agree with Goose. Dont spend too much time on these...