the 2011 annual report of Alaska Airlines contained the following footnote:

5-10 years

consider a Boeing 737-100 airplane that Alaska acquired for $50 million. its useful life is 20 years, and its expected residual value is $6 million. prepare tabular comparison of the annual depreciation and book value for each of the first 3 years of service life under straight-line and DDB depreciation. show all amounts in thousands of dollars (rounded to the nearest thousand). (Note that this is a comparison of methods used for reporting to shareholders. Such methods may differ from those used for reporting income tax authorities).