Consider the Following PERT Network,along with the Completion Times for Each

Consider the following PERT network,along with the completion times for each activity,in days.Use Crystal Ball to enumerate the completion times of all paths in the network.Typically,the longest path in the network dictates the project completion time.Use 1000 replications.

$\begin{array}{|c|c|c|c}\text { Activity } & \text { Optimistic } & \frac{\text { Most }}{\text { Likely }} & \text { Pessimistic } \\\hline 1-2 & 3 & 5 & 7 \\\hline 2-4 & 15 & 20 & 30 \\\hline 4-6 & 16 & 18 & 21 \\\hline 1-3 & 4 & 5 & 6 \\\hline 3-5 & 10 & 15 & 19 \\\hline 5-6 & 16 & 20 & 25 \\\hline\end{array}$
a.What is the average project completion time?
b.What is the probability that the project completion time will exceed 50 days?