27. (10 Points) Ulrich Resources, Ltd. purchased a computer system on January 1, 2019 at a cost of $200,000. The computer was depreciated using the double declining balance method over an estimated five-year life with an estimated residual value of $10,000. On January 1, 2021, the estimate of useful life was changed to a total of 10 years, and the estimate of residual value was change to $0. Calculate the book value at the end of 2020 and depreciation expense for 2021