$($b$)$ Set up and solve an LP model using Excel to crash this project to $24$ days. What is the total crashing cost?

ACTIVITY

IMMEDIATE PREDECESSORS

STANDARD TIME $($Days$)$

STANDARD COST

CRASH TIME $($Days$)$

CRASH COST

A

$--$

$7$

$$2,000$

$5$

$$3,500$

B

A

$10$

$$3,000$

$8$

$$4,700$

C

A

$8$

$$3,400$

$7$

$$3,700$

D

C

$6$

$$1,600$

$4$

$$2,600$

E

C

$7$

$$1,900$

$4$

$$4,000$

F

D$,$E

$5$

$$1,200$

$3$

$$2,800$

G

B$,$C

$11$

$$8,200$

$8$

$$10,900$

H

F$,$G

$4$

$$2,600$

$3$

$$3,800$