Rogers Products uses a periodic inventory system. The companys records show the beginning inventory of PH4 oil filters on January 1 and the purchases of this item during the current year to be as follows: Jan. 1 Beginning inventory 13 units @ $3.00 $ 39.00 Feb. 23 Purchase 15 units @ $3.50 52.50 Apr. 20 Purchase 35 units @ $3.80 133.00 May 4 Purchase 40 units @ $4.00 160.00 Nov. 30 Purchase 20 units @ $5.00 100.00 Totals 123 units $ 484.50 A physical count indicates 23 units in inventory at year-end. Determine the cost of the ending inventory on the basis of each of the following methods of inventory valuation. (Remember to use periodic inventory costing procedures.) (Round your intermediate and final answers to 2 decimal places.) a. Average cost. b. FIFO.