9. Ine population of a city has been increasing at the rate of 3% a year. If the population is now 425,000 , how long will it take the city to grow to a population of 500,000 , assuming that the annual rate of increase remains at 3% ? (5+ years) 10. The sales of a business have been increasing at approximately 7% a year. If the sales in 1989 were $14.2 million, when will sales reach $21 million, assuming that the rate of increase remains at 7% ? Give the answer to the nearest year. 11. A loan company charges 36% a year compounded monthly on small loans. How long will it take to triple money at this rate? Give the answer to the nearest month. ( 37 months) 12. An alumnus leaves $75,000 to a university with the provision that it is to be invested until it amounts to $100,000. From then on the