it is estimated that the average principal owed for student loans in 2017 was $28,650 per student. if market rates go up and the interest rate for student loans increases from 5.05% to 6.8%, estimate how much more interest students will pay over a 10-year repayment period for this average amount owed, at the 6.8% rate as compared with a rate of 5.05%. round all figures to the nearest dollar.