Oday Company uses the periodic inventory system. For May 2012, the beginning inventory consisted of 18,000 units that cost $24 each. During the month, the company made two purchases: 12,000 units at $26 each on May 15, and 6,000 units at $32 each on May 23. The ending inventory on May 31 was 12,000 units. Using the average-cost method, what is the amount of ending inventory for the month of May 2012?; Select one: $348,000. $588,000 $624,000. $312,000