Solve the Problem $C ( x )$ To Produce $x$ Units of Plywood Is Given By

Multiple Choice

Solve the problem. Round to two decimal places unless otherwise indicated.
-If the average cost per unit $C ( x )$ to produce $x$ units of plywood is given by $C ( x ) = \frac { 300 } { x + 10 }$ , what is the unit cost for 40 units?

A) $\$ 7.50$
B) $\$ - 2.50$
C) $\$ 0.75$
D) $\$ 6.00$