$($a$)$ Draw the precedence network.

$($b$)$ What is the probability that the project can be c$4$npleted in $24$ days or less? In $21$ days or less?

$($c$)$ Suppose that now is the end of the seventh day and that activities a & b have been completed while activity $d$ is $50$ percent completed. Three$-$point estimates for the remaining duration of activity $d$ are now $5,6,$ and $7$ days. Activities $c$ and $h$ are ready to begin. Determine the probability of finishing the project by the end of $($a$)$ day $24$ and $($b$)$ day $21.$

Duration in Days

$\backslash$table$[[$Activity$,$Precedes,Optimistic,Most Likely,Pessimistic$],[$a $....,$c$,5,6,7],[$b $...........,$h$,8,8,11],[$c WW$........,$e$,6,8,11],[$d $........,$f$,9,12,15],[,$End,$5,6,9],[$f$,$g$,5,6,7],[$g$...........,$End,$2,3,7],[h.......,$i$,4,4,5],[$i $............,$End,$5,7,8]]$