I just felt like posting the actual formula for COGS:
Beginning inventory + Purchases - Ending inventory = Cost of goods sold
In this instance, it appears that we have beginning inventory of $10,000 plus $5,000 in purchases for a total of $15,000. There were no sales leaving an ending inventory of $15,000. So, $15,000 less $15,000 equals $0 for COGS.
