a gallon of paint will cover approximately 275 square feet. a room in the shape of a cube is to be painted using this paint. If an edge of the room measures 12 feet what is the least number of gallons of paint that must be bought. The floor is not to be painted but the ceiling is
we have that
the surface area of the room is equal to
SA=5b^2 -------> because The floor is not to be painted
where b is the length side of the cube
in this problem
b=12 ft
SA=5(12^2)
SA=720 ft2
divide the surface area by 275 ft2
720/275=2.6 gal
therefore
answer is 3 gallons