n 3: (10 points) A1, B1, B3 FlyArab Airlines purchased Boeing 747-800 on January 1, 2009, at a cost of $70,000,000. The estimated useful life of the aircraft is 40 years, with an estimated salvage value of $10,000,000. On January 1, 2012 the airline revises the total estimated useful life to 30 years with a revised salvage value of $7,000,000. Instructions (a) Compute the depreciation and book value at December 31, 2011 using the straight- line method and the double-declining-balance method. (b) Assuming the straight-line method is used, compute the depreciation expense for the year ended December 31, 2012