3.06 Exponential Growth and Decay 1. Compound Interest. Complete the table to determine the balance A for an investment of $7000.00 at an interest rate of 7% for 20 years compounded n times a year. 12 365 Continuously A 2. A new car is priced at $28,500. It depreciates at a rate of 16% a year. What is the value of the car after 3 years? 3. A diamond ring was purchased 20 years ago at a cost of $500.00. The value of the ring increased by 9% each year. How much is the ring worth today? 4. A beverage you drink has 210 milligrams of caffeine. If the amount of caffeine in your system decreases by 21% each hour, how many milligrams of caffeine would be in your system after 4 hours. 5. The number of cells phones in the United States was 1.2 million in 1995. If the annual increase in the number of phone per year is 21%. In what year will there be 1 billion cell phones in use