Suppose the amounts presented here are basic financial information (in millions) from the 2017 annual reports of Nike and adidas.

		Nike		adidas
Sales revenue		$20,272		$11,335
Allowance for doubtful accounts, beginning		85.8		125
Allowance for doubtful accounts, ending		118		118
Accounts receivable balance (gross), beginning		2,668		1,666
Accounts receivable balance (gross), ending		2,793.0		1,460

a) Calculate the accounts receivable turnover for both companies.

b) calculate the average collection period.