During a violent thunderstorm with very high wind gusts in the third week of March, the broadcast tower for the public radio station WVPR, atop Poor Mountain in Roanoke, collapsed. This greatly reduced the strength of the station’s signal in the area. The station management immediately began plans to construct a new tower. Following is a list of the required activities for building the new tower with optimistic (a), most likely (m), and pessimistic

(b) time estimates

(in days); however, the sequence of the activities has not been designated:

Time Estimates (days)

Activity Activity Description a m b a Removal of debris 5 8 12 b Survey new tower site 3 6 8 c Procure structural steel 15 21 30 d Procure electrical/broadcasting equipment 18 32 40 e Grade tower site 4 7 10 f Pour concrete footings and anchors 10 18 22 g Deliver and unload steel 3 5 9 h Deliver and unload electrical/broadcast equipment 1 2 4 i Erect tower 25 35 50 j Connect electrical cables between tower and building 4 6 10 k Construct storm drains and tiles 10 15 21 l Backfill and grade tower site 4 7 9 m Clean up 3 6 10 n Obtain inspection approval 1 4 7 Using your best judgment, develop a CPM/PERT network for this project and determine the expected project completion time. Also determine the probability that the station signal will be back at full strength within 3 months.

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