(Compound value solving for r ) At what annual rate would the following have to be invested? a. $500 to grow to $1,569.21 in 12 years b. $280 to grow to $518.26 in 8 years c. $50 to grow to $711.59 in 19 years d. $204 to grow to $247.96 in 4 years a. At what annual rate would $500 have to be invested to grow to $1,569.21 in 12 years? \% (Round to the nearest whole percent.)