On January 1, 2011, Canseco Plumbing Fixtures purchased equipment for $30,000. Residual value at the end of an estimated four-year service life is expected to be $2,000. The company expects the machine to operate for 10,000 hours. Calculate depreciation expense for 2011 and 2012 using each of the following depreciation methods:
(a) Straight line,
(b) Sum-of-the-years'-digits,
(c) Double-declining balance, and
(d) Units-of-production using machine hours.

The machine operated for 2,200 and 3,000 hours in 2011 and 2012, respectively.