During a violent thunderstorm with very high wind gusts in the third week of March, the broadcast

Question:

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.