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:

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.

Time Estit (days) Activity Activity Description 12 Removal of debris Survey new tower site Procure structural steel Procure electrical/broadcasting equipment Grade tower site Pour concrete footings and anchors Deliver and unload steel Deliver and unload electrical/broadcast equipment Erect tower 6 21 32 18 40 10 10 25 j Connect electrical cables between tower and building 4 10 35 10 21 k Construct storm drains and tiles Backfll and grade tower site Clean up Obtain inspection approval 15 m 10