A painter is going to paint a room shaped like a cube, with square walls that are 20 ft. on each side. A gallon of paint can be used to cover 400 square feet. How many gallons of paint should the painter buy if he is going to paint the four walls of the room? (1 point)
6 gallons
5 gallons
4 gallons
1 gallon
The total area of the four walls is 4 * (20 ft * 20 ft) = 4 * 400 ft^2 = 1600 ft^2.
Therefore, the painter should buy 1600 ft^2 / 400 ft^2/gallon = 4 gallons of paint. Answer: 4 gallons.