A grader has an initial cost of $220,000 and an estimated useful life of 12 years. The salvage value after 12 years of use is estimated to be $25,000.

 a) What is the annual depreciation amount, if the straight-line method of depreciation accounting is used? 

b) What is the book value at the end of the sixth year, if the sum-of-the-years method of depreciation accounting is used? 

c) What is the book value at the end of the fifth year if the double declining-balance method of depreciation accounting is used?