Inverness Steel Corporation is a producer of flat-rolled carbon, stainless and electrical steels, and tubular products. The company's income statement for the 2021 fiscal year reported the following information ($ in millions): Sales $ 6,200 Cost of goods sold 5,200 The company's balance sheets for 2021 and 2020 included the following information ($ in millions): 2021 2020 Current assets: Accounts receivable, net $ 704 $ 604 Inventories 895 818 The statement of cash flows reported bad debt expense for 2021 of $5 million. The summary of significant accounting policies included the following notes ($ in millions): Accounts Receivable (in part) The allowance for uncollectible accounts was $7 and $4 at December 31, 2021 and 2020, respectively. All sales are on credit. Inventories Inventories are valued at the lower of cost or market. The cost of the majority of inventories is measured using the last-in, first-out (LIFO) method. Other inventories are measured principally at average cost and consist mostly of foreign inventories and certain raw materials. If the entire inventory had been valued on an average cost basis, inventory would have been higher by $470 and $320 at the end of 2021 and 2020, respectively. During 2021, 2020, and 2019, liquidation of LIFO layers generated income of $5, $6, and $24, respectively. Required:

1. Determine the amount of accounts receivable Inverness wrote off during 2021. (Enter your answer in millions.)

2. Calculate the amount of cash collected from customers during 2021. (Enter your answer in millions.)

3. Calculate what cost of goods sold would have been for 2021 if the company had used average cost to value its entire inventory. (Enter your answer in millions.)

4. Calculate the receivables turnover ratio, the inventory turnover ratio, and the gross profit ratio for 2021. (Round "Receivables turnover ratio" and "Inventory turnover ratio" answers to 2 decimal places. Round "Gross profit ratio" answer to nearest percent (i.e., 0.123 needs to be entered as 12%).)