Presented below are selected transactions at Marin Company for 2020. Jan. 1 Retired a piece of machinery that was purchased on January 1, 2010. The machine cost 60,900 on that date. It had a useful life of 10 years with no residual value. June 30 Sold a computer that was purchased on January 1, 2017. The computer cost 39,100. It had a useful life of 5 years with no residual value. The computer was sold for 13,900. Dec. 31 Discarded a delivery truck that was purchased on January 1, 2016. The truck cost 39,780. It was depreciated based on a 6-year useful life with a 3,000 residual value. Journalize all entries required on the above dates, including entries to update depreciation, where applicable, on assets disposed of. Marin Company uses straight-line depreciation. (Assume depreciation is up to date as of December 31,2019 .) (Credit account titles are