Ashley borrows $3,000 for 10 years at 13% annual effective. She pays the interest yearly, and the principal by means of two sinking funds. One-third of the principal is repaid by a sinking fund earning 17% effective annually, and the other two-thirds by a sinking fund earning 12% effective annually.
(a) Find Ashley's total annual payment and the rate of interest she is really paying on her loan.
(b) Redo (a) if Ashley puts one-third of her total sinking fund deposit in the 17% fund and two-thirds into the 12% fund.