An advertisement about the paint that you want to use reads: "Just 2 quarts covers 175 square feet!" If you need to apply two coats of paint on all the walls, how many quarts of paint do you need to buy?

The question isn't really detailed that well, but assuming that you only need to paint 4 walls, you'll need enough paint to cover 175•4 feet. Which is 700ft of paint. Since 2 quarts covers 175 feet you'll need 8 quarts to cover 700 feet. But it says you want to apply TWO coats of paint of all the walls. So the answer is 16 quarts of paint.