where Days of Inventory is days of inventory outstanding, or average inventory divided by the costs of goods and services sold (Cost of goods sold); days sales outstanding is days of sales outstanding, or average accounts receivables divided by daily revenue; and Days Payables Outstanding is days of payment outstanding, which is average accounts payable divided by COGS. If the operating margin (revenue – Cost of goods sold) is constant, we can rewrite Days of Inventory and Days Payables Outstanding, without loss of generality, as