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	2015	2014
Land	$596	$153
Buildings	2,273	1,420
Leasehold equipment	447	304
Network equipment	3,633	3,020
Computer software, office equipment and other	248	149
Construction in progress	622	738
Total	7,819	5,784
Less: Accumulated depreciation	(2,132)	(1,817)
Property and equipment, net	$5,687	$3,967

Depreciation expense on property and equipment was $1.22 billion, $923 million, and $857 million during 2015, 2014 and 2013, respectively. (a) Compute the PPE turnover for 2015 (Sales in 2015 are $17,928 million)

Round answer to two decimal places. ___3.71___ (b) Estimate the useful life, on average, for its depreciable PPE assets.

Round your answer to two decimal places. ________ years (The answer is NOT 5.41 and 5.58) (c) By what percentage are Facebook's assets "used up" at year-end 2015?

Round your answer to two decimal places. _____32.3____%

Please acculate the QUESTION B, thank you