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Quantitative analysis:Networks, PERT, critical path.

Two problems (attached is better formatting):

Environment Recycling, Inc. must clean up a large autormobile tire dump under a state environmental cleanup contract. The tasks, durations (weeks), costs, and predecessor relationships are shown in the table below.

Activity Predecessor(s) Normal Time Crash Time Normal Cost Crash Cost
A - 5 4 400 750
B A 12 9 1000 2200
C A 7 6 800 1100
D C 6 5 600 1000
E B, D 8 6 1200 2200
F D 3 2 800 1000
G D 3 2 500 650
H E 4 3 400 600
F, G, H 6 5 900 1300

a. Draw the project network.
b. Identify the critical path(s).
c. What is the total project-completion time and total cost?
d. What is the total project-completion time and lowest-cost solution if the state wants to complete the project 3 weeks early?


A competitor of Kozar International, Inc. has begun marketing a new instant-developing film project. Kozar has had a similar product under study in its R&D department but has not yet been able to begin production. Because of the competitor's action, top managers have asked for a speedup of R&D activities so that Kozar can produce and market instant film at the earliest possible date. The predecessor information and activity time estimates in months are shown here:

Activity Immediate Predecessors Optimistic Time Most Probable Time Pessimistic Time
A - 1 1.5 5
B A 3 4 5
C A 1 2 3
D B, C 3.5 5 6.5
E B 4 5 12
F C, D, E 6.5 7.5 11.5
G F 5 9 13

a. Draw the project network.
b. Develop an activity schedule for this project using early and late start and finish times, compute activity slack time, and define the critical activities.
c. What is the probability the project will be completed in time for Kozar to begin marketing the new product within 24 months?


Solution Summary

The problem deals with estimating project duration, critical path, and precedence diagram.