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Exercise 143 Sisco Co. purchased a patent from Thornton Co. for $620,000 on July 1, 2012. Expenditures of $119,000 for successful litigation in defense of the patent were paid on July 1, 2015. Sisco estimates that the useful life of the patent will be 20 years from the date of acquisition. Prepare a computation of the carrying value of the patent at December 31, 2015