Calculate depreciation at each year end that applies

Question

Machinery purchased on January 1, 2011:

Cost of machinery                               250,000

Estimated residual value                       10,000

Estimated useful life:

            Years                                       6 years

            Units of production                200,000 machine hours

Required:

Calculate depreciation at each year end that applies:

1) Straight-line method

2) Units of production method

Assumption: Machinery machine hours on the 1^st year, 66,000; 2^nd  year, 60,000; 3^rd year, 38,000; 4^th year, 22,000; 5^th year, 8,000; and 6^th year, 6,000

3) Double-declining method