The table below gives the duration estimates in days for a construction projection. $\backslash$begin$\{$tabular$\}\{|$l$|$l$|$l$|$l$|$l$|\}\backslash$hline Activity & Predecessor & Optimistic & Most Likely & Pessimistic $\backslash \backslash \backslash$hline A & $-$ & $2$ & $4$ & $7\backslash \backslash \backslash$hline B & $-$ & $1$ & $3$ & $6\backslash \backslash \backslash$hline C & $-$ & $3$ & $5$ & $8\backslash \backslash \backslash$hline D & A & $9$ & $11$ & $20\backslash \backslash \backslash$hline E & A & $2$ & $5$ & $7\backslash \backslash \backslash$hline F & B & $6$ & $9$ & $20\backslash \backslash \backslash$hline G & C & $5$ & $10$ & $22\backslash \backslash \backslash$hline H & E$,$ F & $3$ & $5$ & $12\backslash \backslash \backslash$hline I & D & $4$ & $7$ & $9\backslash \backslash \backslash$hline J & G & $6$ & $9$ & $13\backslash \backslash \backslash$hline K & H$,$J & $3$ & $4$ & $6\backslash \backslash \backslash$hline L & I,K & $7$ & $10$ & $23\backslash \backslash \backslash$hline $\backslash$end$\{$tabular$\}3\mathrm{.}1$ Determine the expected completion time for each activity. Round off answers to the nearest whole number. $3\mathrm{.}2$ Construct an AON network for the activities of this contract. $(5$ marks$)3\mathrm{.}3$ Determine the critical path for the project by calculating the slack for each activity. $(5$ marks$)(10$ marks$)$