On January 2, Year 1, Collins Company purchased equipment costing $43,200. The equipment has an estimated salvage value of $6,120 and an estimated useful life of 20 years. Collins Company uses straight-line depreciation. During Year 4, new information suggests that the equipment will have a total useful life of 9 years and a revised salvage value of $5,760. Required: 1.Compute depreciation expense for Year 4. 2.Compute the book value of the equipment at the end of Year 4.