9 (a) Janna and Kamal each invest $8000. At the end of 12 years, they each have $12 800. (i) Janna invests in an account that pays simple interest at a rate of r% per year. Calculate the value of r. r = ................................................ [3] (ii) Kamal invests in an account that pays compound interest at a rate of R% per year. Calculate the value of R. R = ................................................ [3] (b) The population of a city is growing exponentially at a rate of 1.8% per year. The population now is 260 000. Find the number of complete years from now when the population will first be more than 300 000. ........................................ years [3] © UCLES 2024 0580/42/F/M/24 17 3 2