A factory machine was purchased for $246000 on January 1, 2017. It was estimated that it would have a $36000 salvage value at the end of its 5-year useful life. It was also estimated that the machine would be run 50000 hours in the 5 years. If the actual number of machine hours ran in 2017 was 5000 hours and the company uses the units-of-activity method of depreciation, the amount of depreciation expense for 2017 would be $49200. $21000. O $24600. $42000.