A piece of equipment having a negligible salvage and scrap value is estimated to have a service life of 10 years. The original cost of the equipment was $40,000. Determine the following:
(a) The depreciation charge for the fifth year if double declining-balance depreciation is used.
(b) The depreciation charge for the fifth year if sum-of-the-years-digits depreciation is used.
(c) The percent of the original investment paid off in the first half of the service life using the double declining-balance method.
(d) The percent of the original investment paid off in the first half of the service life using the sum-of-the-years-digits method.