Question $6(9$ marks$)$

A project manager has compiled a list of major activities that will be required to install a new

computer system. The duration of each activity can be reduced by a maximum of two weeks. The

crashing cost for each week is provided in the table below:

Crashing Costs

Activity Immediate predecessor$($s$)$ Normal

Duration $($weeks$)$

$1$st Week $2$nd Week

A $-5$ $$8$ $$15$

B A $6722$

C B$,$ E $31725$

D $-3921$

E D $788$

F $-51021$

G F $51523$

H E$,$ G $51224$

End C$,$ H

a$)$ Determine the minimum$-$cost crashing if the goal is to shorten the project by three