Exercise 6-21A (Algo) Performing ratio analysis using real-world data LO 6-11 Heatwave Gaming develops, markets, and publishes electronic games. ZipTrain is one of the largest railway networks in the nation, with over 27,000 miles of railroads. The following data were taken from each of the companies' December 31,2017 , annual reports. Revealing which data relate to which company was intentionally omitted. The dollar amounts are in millions. Required a. Calculate depreciation costs as a percentage of sales for each company. (Round your percentage answers to 2 decimal places (i.e., 0.0123 is entered as 1.23% ).) b. Calculate property, plant, and equipment as a percentage of total assets for each company. (Round your percentage answers to 2 decimal places (i.e., 0.0123 is entered as 1.23% ). c. Based on the information now avaliable to you, which company is Ziptrain? d. Which company appears to be using its assets most efficiently