Oahu Kiki tracks the number of units purchased and sold throughout each accounting period but applies its inventory costing method at the end of each month as if it uses a periodic inventory system. Assume Oahu Kiki's records show the following for the month of January. Sales totalled 420 units. Required: 1. Calculate the number and cost of goods available for sale. 2. Calculate the number of units in ending inventory. 3. Calculate the cost of ending inventory and cost of goods sold using the (a) FIFO and (b) weighted average cost methods. (Do not round Weighted average cost per unit. Round your final answers to the nearest dollar amount.)