QUESTION $4(20$ Marks$)$

The table below gives the duration estimates in days for a construction projection.

Activity Predecessor Optimistic Most Likely Pessimistic

A $-247$

B $-136$

C $-358$

D A $91120$

E A $257$

F B $6920$

G C $51022$

H E$,$ F $3512$

I D $479$

J G $6913$

K H$,$J $346$

L I,K $71023$

$4\mathrm{.}1$ Determine the expected completion time for each activity. Round off answers to the nearest whole

number.

$(5$ marks$)$

$4\mathrm{.}2$ Construct an Activity$-$on$-$node $($AON$)$ network for the activities of this contract. $(5$ marks$)$

$4\mathrm{.}3$ Determine the critical path for the project by calculating the slack for each activity. $(10$ marks$)$