Finding the required interest rate Your parents will retire in 18 years. They currently have $330,000, and they think they will need $1,700,000 at retirement. What annual interest rate must they earn to reach their goal, assuming they don't save any additional funds? Round your answer to two decimal places. Time to reach a financial goal You have $46,899.31 in a brokerage account, and you plan to deposit an additional $4,000 at the end of every future year until your account totals $260,000. You expect to earn 10% annually on the account. How many years will it take to reach your goal? Round your answer to two decimal places at the end of the calculations. years Time for a lump sum to double How long will it take $100 to double if it earns the following rates? Compounding occurs once a year. Round each answer to two decimal places. a. 7%. year(s) b. 14%. year(s) C. 17%. year(s) d. 100% year(s)