A loan is issued to be repaid with interest only payments on the loan at 10%. The borrower will also use a sinking fund with an interest rate of 8% to accumulate the amount of the loan at the end of the term. Assuming year-end payments to the loan and the sinking fund and a term of 3 years. Which interest rate is closest to an equivalent interest rate for an amortization loan with the same total annual payment?

That is what interest rate would for a loan would have the same total payment as the sinking fund loan?