15. What amount must be invested on 1 April 2019 at a rate of 10.5% per year, compounded quarterly, so that an amount of R345 756 will be in the account on 1 October 2026? (a) R154 853.65 (b) R158 918.56 (c) R163 090.17 (d) R167 371.29 (e) None of the above. 16. There is an amount of R50 000 in an account today earning interest at a rate of 5% per year. What amount will be in the account in exactly ten years if the interest rate changes to 9% per year in exactly four years? (a) R52 122.83 (b) R60 775.31 (c) R101 926.28 (d) R85 789.31 (e) None of the above. 17. A person decided to invest money at the end of each quarter. His initial investment amount is R500 but thereafter, starting with the second quarter, he decreased the amount by R30 each time. Find the accumulated investment after 2 years if interest is compounded at i(4) = 16% p.a. (Fill in your answer on the answer sheet.) (17- (-) (3 marks) IZMERO 18. What amount can be borrowed at 10% p.a., compounded half-yearly, if it is to be repaid by regular half-yearly payments, the first payment being R4 000 (payable at the end of the first half- year) and the subsequent payments decreasing by R400 per half-year until a final 10th payment of R400 is made. (Fill in your answer on the answer sheet.) (3 marks) [(ta), - la-ni) + Pan