QUESTION FOUR

A project has the following characteristics:

$\backslash$table$[[$Activity$,$Optimistic time,Pessimistic time,Mast likely time$],[1-2,1,5,1\mathrm{.}5],[2-3,1,3,2],[2-4,1,5,3],[3-5,3,5,4],[4-5,2,4,3],[4-6,3,7,5],[5-7,4,6,5],[6-7,6,8,7],[7-8,2,6,5],[7-9,5,3,5],[8-10,1,7,5],[9-10,3,,5]]$

$($a$)$ Construct the network

$($b$)$ Find the critical path and variance for each event

$($c$)$ Find the project duration at $95\%$ probability.