#### Answer

a. 40 pounds.
b. $\$ 280$

#### Work Step by Step

$C(x)=3x+160$
R(x)=px, where p is the price per unit
$R(x)=7x$
a.
Break-even quantity: the number of units x for which C(x)=R(x)
$3x+160=7x$
$160=4x$
$40x=x$
The break-even quantity is 40 pounds.
b.
$R(40)=7\cdot 40=280$