Using the network above and the additional information

below, find

a$.$ The crash cost per day

b$.$ Which activities should be crashed to meet a project dead

line of $13$ days at minimum cost. Assume partial crashing

is allowed.

Activity

A

B

C

D

Crash

Time

$($days$)$

$3$

$1$

Crashed

Cost

$($total$)$

$$500$

Normal

Time

$($days$)$

$4$

$325$

$4$

$3$

$550$

$250$

$3$

$7$

$5$

Normal

Cost

$$300$

$250$

$400$

$150$