Below are the data for a Time$-$Cost CPM scheduling model. Times are in days

and costs include both direct and indirect costs.

Activity $($A$,$B$,$C$,$D$,$E$)$

Immediate predecessor A is none. B is A$.$ C is A$.$ D is B and C$.$ E is D$.$

Normal time for

A: $3$

B: $4$

C:$4$

D:$3$

E:$2$

Crash Time for

A: $2$

B: $3$

C:$3$

D:$2$

E:$1$

Normal cost $($in dollars$)$ for

A: $20$

B: $30$

C:$20$

D:$50$

E:$50$

Crash cost $($ in dollars for$)$

A: $40$

B: $45$

C:$35$

D:$60$

E:$55$