P6-38. Interpreting and Applying Disclosures on Property and Equipment Following are selected disclosures from the 10-K report of Facebook Inc. Property and Equipment, Net $ millions Land Buildings Network equipment Computer software, office equipment and other... . Total 2015 2014 1,420 304 3,020 149 738 5,784 248 622 Depreciation expense on property and equipment was $1.22 billion, $923 million, and $857 million during 2015, 2014 and 2013, respectively. Required a. Compute the PPE turnover for 2015 (Sales in 2015 are $17,928 million). b. Estimate the useful life, on average, for its depreciable PPE assets. c. By what percentage are Facebook's assets "used up" at year-end 2015? What implication does the assets used up computation have for forecasting cash flows? model what types of costs are included in the $622 million on the balance sheet? d. Consider the ratios in parts a, b, and c. Interpret them in light of the company's age and business e. The list of PPE assets includes an asset labeled "Construction in progress