Rush Trainer purchased a houseboat for $165,000. The financing company requires a 15% down payment for a 30-year loan at 7%. At the end of 30 years, what will be the total amount of interest charged?

Rush Trainer purchased a houseboat for $165,000. The financing company requires a 15% down payment for a 30-year loan at 7%. At the end of 30 years, what will be the total amount of interest charged? (Hint: First subtract the down payment from the purchase price to find the amount to be financed.)