Sandblasting equipment acquired at a cost of $42,000 has an estimated residual value of $6,000 and an estimated useful life of 10 years. It was placed in service on October 1 of the current fiscal year, which ends on December 31, 20Y5.

a. Determine the depreciation for 20Y5 and for 20Y6 by the straight-line method.

b. Determine the depreciation for 20Y5 and for 20Y6 by the double-declining-balance method.