Trevor bought 8 gallons of paint to paint his house. he used all but 1 quarry. how many quarts of paint did trevor uae?

Trevor used 31 quarts of paint.

There are 4 quarts to a gallon. He did not use all 8 gallons of paint, which would be 32 quarts. With one quart remaining, this shows Trevor used 31 quarts of paint.