Super Sale Company sold 300 washing machines on April 10th, 2015, for $4,000 a piece, together with a 1-year warranty. Maintenance on each washing machine during the warranty period is estimated to be $170. Actual warranty costs (inventory) incurred in 2015 were $ 9,000. Required: Prepare entries to record the following: a) Sale of the washing machines. b) Related warranty costs. c) The accrual on December 31, 2015