Direct materials inventory, January 1 $ 2,520 Direct materials inventory, December 31 2,088 Work-in-process inventory, January 1 5,440 Work-in-process inventory, December 31 6,110 Finished goods inventory, January 1 22,320 Finished goods inventory, December 31 38,770 Cost of goods manufactured during this year 611,650 Total manufacturing costs 612,320 Direct labor 270,400 Manufacturing overhead 225,000 Average selling price per unit 18 Gross margin percentage (as a percentage of sales) 38 % if this is the infomation given how can I find the direct materials used and the purchases of direct materials??