Question

How many gallons of paint are needed to paint the walls of a rectangular prism shaped room that is 20 ft by 13 ft and 8 ft high if 1 gallon of paint covers 40 square feet?

Answer 1

20 Gallons of paint are needed.

Explanation:

Surface Area of a rectangular prism formula is 2 * length * width + 2 * length * height + 2 * width * height.

Substituting the given values, we get:

SA = 2 * 20 * 13 + 2 * 20 * 8 + 2 * 13 * 8

SA = 1048

Area of the floor is length * width. 20 * 13 = 260

Subtract the area of the floor from SA as we do not paint the floor. 1048 - 260 = 788

The number of gallons of paint is 788 / 40 as each gallon covers 40 sq feet. We round this number up to ensure that we have more than enough paint. 788 / 40 = 19.7. Rounding that to 20.

Therefore, 20 gallons of paint are needed.