In its 1998 annual report, McDonald’s Corporation reports beginning total assets of $18.2 billion; ending total assets of $19.8 billion; beginning property, plant, and equipment (at cost) of $20.1 billion; ending property, plant, and equipment (at cost) $21.8 billion; ending accumulated depreciation of $5.7 billion; depreciation expense of $808 million; and net sales of $12.4 billion.

(a) Compute the average useful life of McDonald's property, plant, and equipment.

(b) Compute the average age of McDonald's property, plant, and equipment.

(c) Compute McDonald’s asset turnover ratio.