On January 1, 20X1, WebHelper Inc. purchased equipment for $150,000. The estimated service life of the equipment is 9 years and the estimated residual value is $5,000. The equipment is expected to produce 290,000 units during its useful life. In 20X3, WebHelper Inc. revised its estimate of the useful life of the asset from 9 to 12 years and estimated that the asset will not have a residual value at the end of its useful life. Calculate depreciation for 20X3 assuming that WebHelper Inc. has a December 31 fiscal year end using the depreciation methods below. Round all computations to the nearest dollar. a. Sum-of-the-years' digits