For questions $3$ and $4,$ do the following.

$($a$)$ Construct an activity network for the preceedance tables. $[3]$

$($b$)$ Calculate the event times $($earliest start times and latest start times$),$ and

hence find the critical path. $[6]$

$($c$)$ Calculate the total, independent and interfering float times, for each activity. $[12]$

$($d$)$ Give a critical path. $[2]$

$3.$

Activity Duration Immediate

Predecessors

A $7-$

B $6-$

C $8-$

D $4$ A

E $5$ A

F $9$ B$,$ E

G $3$ B$,$ E

H $2$ C

I $4$ D$,$ F

J $3$ H

$4.$

Activity Duration Immediate

Predecessors

A $3-$

B $8-$

C $4-$

D $3$ A

E $7$ B$,$ C

F $5$ B$,$ C

G $3$ D

H $8$ D

I $3$ E$,$ G

J $8$ F

K $2$ J