A scraper will be purchased for a cost of $420,760. After a useful life of 5 years, it will be sold for $40,000. Assume interest of 15% for borrowing money, 4% for risk, and 3% as the equivalent interest rate for taxes, insurance, and storage. What is the annual ownership cost? Approximately how many hours per year must the scraper be used to be able to charge it out at an hourly cost of $44.30.