Three years ago Jake borrowed R7 500 from Martha. The condition was that he would pay her back in seven years’ time at an interest rate of 11,21% per year, compounded semi-annually. Six months ago he also borrowed R25 000 from Martha at 9,45% per year, compounded monthly. Jake would like to pay off his debt four years from now.

The amount of money that Jake will have to pay Martha four years from now is