$4.$ Economy Power requires an upgrade of a complex piece of equipment in their network. There are

nine activities required to complete the upgrade. The table below summarizes the relationship of each

activity and their duration. It also included the costs of each activity and crash costs if needed. $(20$

points$)$

Activity Immediate

Predecessors

Normal

Duration

$($hours$)$

Crash

Time

$($hours$)$

Normal

Cost

Crash cost

A None $53300500$

B A $21350500$

C A $1212600600$

D None $32125725$

E B $55225225$

F D $11275875$

G B $74200800$

H E$,$C $215001000$

I G$.$F $108125725$

J H$,$I $66365365$

a$.$ Draw the AON network $(2$ points$)$

b$.$ Label the network completing the nodes for ES$,$EF$,$LS$,$LF $(5$ points$)$

c$.$ Label the slack time $(1$ point$)$

d$.$ Identify the critical path $(1$ point$)$

e$.$ What is the earliest finish time? $(1$ point