Companies in the tire manufacturing business use a lot of property, plant, and equipment. Tyrell Rubber and Tire Corporation and Maxwell Rubber and Tire Manufacturing are two of the leading manufacturers. In additiion, Tyrell also operates over 1,000 tire service center outlets. Tyrell Rubber & Tire $2,908 180 Maxwell Rubber & Tire $15,575 935 Sales Depreciation and depletion costs Property, plant, and equipment (net of accumulated depreciation) Total assets Depreciation method Depletion method Estimated life of assets Buildings Machinery and equipment Net income 975 2,632 Straight-line Units of production 6,126 16,972 Straight-line Units of production 10 to 40 years 2 to 14 years $102 3 to 45 years 3 to 40 years $860 Required a. Calculate depreciation costs as a percentage of sales for each company. b. Calculate property, plant, and equipment as a percentage of total assets for each company. c. Based only on the percentages calculated in Requirements a and b, which company appears to be using its assets most efficiently? d. Calculate the return-on-assets ratio for each company. Based on this ratio, which company appears to be using its assets most efficiently? (Enter your answers as a percentage rounded to 1 decimal place (i.e., 0.123 should be entered as 12.3).)