Interest rate (with changing years). Keiko is looking at the following investment choices and wants to know what annual rate of return each choice produces. a. Invest $420.00 and receive $615.33 in 11 years. b. Invest $3,800.00 and receive $12,349.58 in 18 years. c. Invest $30,365.89 and receive $140,000.00 in 24 years. d. Invest $32,452.49 and receive $1,500,000.00 in 30 years. a. What annual rate of return will Keiko earn if she invests $420.00 today and receives $615.33 in 11 years? % (Round to two decimal places.)