The following data refer to one year for Monroe Fabricators. Fill in the blanks. Direct materials inventory, January 1 $ 2,450 Direct materials inventory, December 31 Work-in-process inventory, January 1 2,920 Work-in-process inventory, December 31 3,850 Finished goods inventory, January 1 1,940 Finished goods inventory, December 31 350 Purchases of direct materials 15,910 Cost of goods manufactured during the year 53,960 Total manufacturing costs Cost of goods sold Gross margin 55,550 47,820 Direct labor Direct materials used Manufacturing overhead Sales revenue 14,560 13,780