#### Answer

a. 5 cartons
b. $\$ 2000$

#### Work Step by Step

$C(x)=200x+1000$
R(x)=px, where p is the price per unit
$R(x)=400x$
a.
Break-even quantity: the number of units x for which R(x)=C(x)
$200x+1000=400x$
$1000=200x$
$5=x$
The break-even quantity is 5 cartons.
b.
$R(5)=$ 400(5) $=2000$