Cherese needs to buy some cardboard to build a box 10 inches long, 9 inches wide, and 7 inches high. If she purchases 500 square inches of cardboard, how much will be left over?

Question

A. 426 in squared
B. 446 in squared
C. 54 in squared
D. 406 in squared

Answer 1

To find the total surface area of the box, we need to calculate the surface area of each side and add them all together.

The top and bottom of the box are both 10in by 9in = 90in squared each.
The front and back of the box are both 10in by 7in = 70in squared each.
The two sides of the box are both 9in by 7in = 63in squared each.

Total surface area = 2(90) + 2(70) + 2(63) = 180 + 140 + 126 = 446 in squared.

Since Cherese purchased 500 in squared of cardboard and the box requires 446 in squared, the amount left over will be 500 in squared - 446 in squared = 54 in squared.

Therefore, the answer is C. 54 in squared.