Nike, Inc. had the following information for the year 2023:

23. 
    
    • Beginning Inventory: $6 billion
    • Purchases: $42 billion
    • Ending Inventory: $8 billion Calculate: a) Cost of Goods Sold (COGS). b) Inventory Turnover Ratio. c) Days Sales Outstanding (DSO) if the accounts receivable at the beginning of the year were $12 billion and at the end of the year were $15 billion.