you have an outstanding student loan with required payments of per month for the next four years. the interest rate on the loan is apr​ (compounded monthly). now that you realize your best investment is to prepay your student​ loan, you decide to prepay as much as you can each month. looking at your​ budget, you can afford to pay an extra a month in addition to your required monthly payments of ​, or in total each month. how long will it take you to pay off the​ loan?