Shown below is activity for one of the products of Denver Office Equipment: January 1 balance, 500 units @ $55 per unit $27.500 Purchases: January 10: 500 units @ $60 per unit January 20:1,000 units @ $63 per unit Sales January 12, 800 units Janar 28.250 units a compute the Sanuary 31 ending inventory and cost of goods sold for January, assuming Denver UFO and a perpetual inventory system. b. Compute the January 31 ending inventory and cost of goods sold for January, assuming Denvers FIFO and a perpetual inventory system e Compute the January 31 ending inventory and cost of goods sold for January, assuming Denver uses Weighted Average and a periodic inventory system