A reactor will be purchased for $ 10,000 for use in a chemical process. The life of the reactor is 5 years, and at the end of the 5th year, the scrap value is $ 500. Calculate the annual depreciation to be reserved for the reactor; 1. a) Declining balance (Matheson) method, 2. b) Sum of the years-digits method, 3. c) If annual interest rate is 10%, sinking -fund method