Number Cost Total of Units Per Unit Cost Inventory, Jan. 1 12 $299 $3,588 First purchase (May 12) 15 306 4,590 Second Purchase (July 9) 21 308 6,468 Third purchase (Oct. 4) 8 315 2,520 Fourth purchase (Dec. 18) 17 320 5,440 Goods available for sale 73 $22,606 Units sold during the year 51 Inventory, Dec. 31 22 Instructions a. Using periodic costing procedures, compute the cost of the December 31 inventory