One gallon of paint covers about 400 square feet. Someone needs to paint all four walls of a room that are 5 yards long, 4 yards wide, and 3 yards high. About how many gallons will be used? Okay, I am kind of stuck on the walls of the room being 4 yards wide. Is the width extra information? I tried converting this to feet and then just using 15x9x4 + 4x9x4 to get 684 and then 684/400=1.71, but I don't think this is right. I also tried 15x12x9x4 to get 6480 and then divided by 400 to get 16.2. I also tried converting to cubic feet and then divide by height but that ended up seeming not needed. I know this does not look like an algebra problem but it was given in my algebra class. Thanks for any help.