Question

Beth is moving into a new house and purchased cardboard boxes for packing her things. Each cardboard box has a square base and a height that is 5 inches shorter than the side length of the base. If x represents the side length of the base, which of the following functions represents the surface area, S, of the cardboard box?
A. S(x) = 6x2 - 20x
B. S(x) = 6x2 + 20x
C. S(x) = 2x2 - 10x
D. S(x) = 2x2 + 10x

Answer 1

Answer:

A

Step-by-step explanation:

Does the box have a lid?

Base Area = x * x = x^2

One side = x(x - 5) and there are 4 such sides.

4 sides = 4*x*(x-5) = 4x^2 - 20x

Since there are no answers with just 5x^2 the answer is that the boxes must have a lid

Lid + base = x^2 + x^x

Lid + base = 2x^2

Four sides = 4x^2 - 20x

Total = 6x^2 - 20x

Answer: A