A homeowner called in a painter to paint the bedroom walls. The bedroom is 18 ft. long, 12 ft. wide. The room has one door that is 3 ft. by 7 ft. and three windows each 3 ft. by 5 ft. The doors and windows do not have to be painted. A gallon of paint can cover 300 ft squared. A hired painter claims he will need 4 gallons show the his estimate is to high