A second-hand bulldozer acquired at the beginning of the fiscal year at a cost of $58,000 has an estimated salvage value of $8000 and an estimated useful life of 12 years. Determine the following:
(a) The amount of annual depreciation by the straight-line method,
(b) The amount of depreciation for the third year computed by the declining balance forward,
(c) The amount of depreciation for the second year computed by the sum-of-years'-digits method.