A Closed Box with a Square Base Is to Have $C ( x ) = 10 x ^ { 2 } + \frac { 40 } { x }$

Multiple Choice

A closed box with a square base is to have a volume of 10 cubic meters.The material for the top and bottom of the box costs $5 per square meter,and the material for the sides costs $1 per square meter.Express the construction cost of the box as a function of the length of its base,x.

A) $C ( x ) = 10 x ^ { 2 } + \frac { 40 } { x }$ dollars
B) $C ( x ) = x ^ { 2 } + 40 x + 2$ dollars
C) $C ( x ) = 2 x ^ { 2 } + \frac { 2 } { x } + 10$ dollars
D) $C ( x ) = 2 x ^ { 2 } + \frac { 10 } { x }$ dollars