what is the average sale period for 2020?

A Q S 2020 Sales ($30,000,000 are on account) 40,000,000 Cost of goods sold (23,000,000) Gross profit 17,000,000 Selling expenses (3,000,000) Administrative expenses (200,000) Total operating expenses (3,200,000) Operating income 13,800,000 Interest expense (175,000) Tax expense (2,000,000) Net income 11,625,000