Hawaiian Specialty Foods purchased equipment for $ 30,000. Residual value at the end of an estimated four-year service life is expected to be $ 3,000. The machine operated for 3,100 hours in the first year, and the company expects the machine to operate for a total of 20,000 hours. Calculate depreciation expense for the first year using each of the following depreciation methods:
(1) Straight-line
(2) Double-declining-balance
(3) Activity-based.