Environment Recycling Inc. must clean up a large automobile tire dump under a st
ID: 432219 • Letter: E
Question
Environment Recycling Inc. must clean up a large automobile tire dump under a state environmental cleanup contract. Suppose that some of the activities in the Environment Recycling Inc. situation can be crashed. The following table shows the crash times and costs associated with performing the activities at their original (normal) times and also for the crash times.
Choose the correct network for the project.
The correct network is -Select-network Anetwork Bnetwork Cnetwork DItem 1 .
Identify the critical path.
The critical path is -Select-A-B-E-H-ID-F-ID-E-H-ID-G-IA-C-E-H-IItem 2 .
What is the total project completion time? Round your answer to the nearest whole number.
weeks
What is the lowest-cost solution if the state wants to complete the project three weeks early? Round your answer for the project duration to the nearest whole number and the answer for the total cost to the nearest dollar.
The total cost of a(an) -week project-completion schedule is $ .
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Environment Recycling Inc. must clean up a large automobile tire dump under a state environmental cleanup contract. Suppose that some of the activities in the Environment Recycling Inc. situation can be crashed. The following table shows the crash times and costs associated with performing the activities at their original (normal) times and also for the crash times.
Activity Immediate
Predecessors Normal
Time Crash
Time Normal
Cost Crash
Cost A — 6 5 $420 $570 B A 9 7 1,950 2,550 C A 8 7 880 1,080 D — 7 6 660 960 E B, C, D 9 7 1,700 2,100 F D 4 2 820 1,320 G D 4 3 560 810 H E 5 4 460 670 I F, G, H 7 5 750 1,350
Choose the correct network for the project.
The correct network is -Select-network Anetwork Bnetwork Cnetwork DItem 1 .
A. B. C. D.Identify the critical path.
The critical path is -Select-A-B-E-H-ID-F-ID-E-H-ID-G-IA-C-E-H-IItem 2 .
What is the total project completion time? Round your answer to the nearest whole number.
weeks
What is the lowest-cost solution if the state wants to complete the project three weeks early? Round your answer for the project duration to the nearest whole number and the answer for the total cost to the nearest dollar.
The total cost of a(an) -week project-completion schedule is $ .
Explanation / Answer
The correct precedence diagram is (c) because, for all others, Activity-D has some predecessors which are wrong! Activity-D must not have any predecessors as per the table.
The critical path is A-C-E-H-I
Total project completion time = 35 weeks
Slope = (Crash cost - Normal Cost) / (Normal time - Crash time)
From 35 weeks to 34 weeks
The critical path is A-C-E-H-I.
Among the critical activities A, C, E, H, and I, Activity-A has the minimum slope of $150. So, crash it by 1 week.
From 34 weeks to 32 weeks
The critical path is still A-C-E-H-I.
Among the critical activities A, C, E, H, and I, Activity-E has the minimum slope of $200. So, crash it by 2 weeks.
So, the project will be completed in 32 weeks (crashing 3 weeks from 35 weeks of normal schedule).
The total cost = total normal cost + {crash cost} = $8,200 + {$150 + 2 x $200} = $8,750
Project paths Normal time duration A-C-E-H-I 35 B-E-H-I 30 D-E-H-I 28 D-G-I 18 D-F-I 18Related Questions
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