A machine was purchased for $54,000 and it was estimated to have a $9,000 salvage value at the end of its useful life. A monthly depreciation expense of $600 was recorded using the straight-line method. The annual depreciation rate is a. 12.8% b. 20% c. 16% d. 1.6% The interest charged on a $300,000 note payable, at the rate of 6%, on a 90 -day note would be