Question

The Durango Paper Company has identified eight activities that need to be completed in order to comply with new EPA air emission standards. Information about these activities are shown below. Activity Description Immediate Predecessor Average Time (weeks)  A Build internal components -- 2  B Modify roof floor -- 3  C Construct air stack A 2  D Pour concrete frame A,B 4  E Build high temp. burner C 4  F Install control systems C 3  G Install air pollution device D,E 5  H Inspect/test F,G 2   Draw a network diagram that represents this project (use Activity on Node convention): Identify all paths and path durations. Path1. A(C(F(H (9 weeks) Path2. A(C(E(H (10 weeks) Path3. A(C(E(G(H (15 weeks) Path4. A(D(G(H (13 weeks) Path5. B(D(G(H (14 weeks) Indicate the critical path(s) and activities.  A C E G H (15 weeks) The project manager at Durango Paper Company wants to know the probability of completing this project in 15 weeks or less. The following additional information has been collected: Activity Optimistic Time Likely Time Pessimistic Time  A 1 2 3  B 2 3 4  C 1 2 3  D 2 4 6  E 1 4 7  F 1 2 9  G 3 4 11  H 1 2 3   Activity Optimistic Time Likely Time Pessimistic Time Estimated Time Variance S.D  A 1 2 3 2 0.11 0.33          B 2 3 4 3 0.11 0.33  C 1 2 3 2 0.11 0.33          D 2 4 6 4 0.44 0.67          E 1 4 7 4 1.00 1.00          F 1 2 9 3 1.78 1.33          G 3 4 11 5 1.78 1.33          H 1 2 3 2 0.11 0.33                  25 5.44 2.33   Z= (15-25)/2.33 = -4.29 P(z<=15) = 0.000009 Probability of completing in 15 weeks or less = 3. Durango Paper Company has been given 12 weeks to install air pollution equipment or face a court-ordered penalty of $1500 per week beyond 12 weeks. Using the following, identify what activities should be crashed each week and how many weeks should be crashed to minimize total costs. Activity Normal Time (wks) Crash Weeks Available Crash Cost per Week Crashed By Total Cost   A 2 1 750 1 750   B 3 1 500 1 500   C 2 1 1000 1 1000   D 4 3 800 3 2400   E 4 2 750 2 1500   F 3 2 500 2 1000   G 5 1 1200 1 1200   H 2 1 3000 1 3000   Total 25 12  12 11350    Extra Cost if the weeks are not crashed : 13 * 1500 = 19500 Extra Cost after crashing = 11350 +1500 = 12850 Optimal number of weeks crashed: Activities crashed by week: Total cost after optimizing crashing costs:

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  • CreatedAugust 26, 2013
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