18. A company purchased a machine on January 1 of the current year for $750,000. Calculate the annual depreciation expense for each year of the machine's life (estimated at 5 years or 20,000 units, with a salvage value of $75,000 ) using each of the below-mentioned methods. During the machine's 5 -year life its units produced were: 3,000;4,000;5,000;6,000; and 4,000 hours. 19. A company purchased an ore mine for $1,560,000. The property was estimated to contain 13,000,000 tons of ore. In the current year, the company removed and sold 263,000 tons of ore. Calculate the depletion expense for the current year. 20. Make the general journal entry if: Plenty Company established a petty cash fund of $150 on natahor 1