4. A loan of 40,000 is being repaid by 12 equal installments made at the end of each year at 9% interest effective annually. Immediately after payment number 7, the loan is renegotiated as follows: (i) The borrower will make 5 annual payments of K to repay the loan, with the first payment made 2 years from the date of renegotiation. (ii) The interest rate is changed to 10.5% effective annually. Calculate K.