(Compound value solving for r) At what annual rate would the following have to be invested? a. $500 to grow to $1,126.10 in 12 years b. $310 to grow to $531.29 in 7 years c. $47 to grow to $611.99 in 21 years d. $220 to grow to $312.07 in 6 years a. At what annual rate would $500 have to be invested to grow to $1,126.10 in 12 years? % (Round to the nearest whole percent.) b. At what annual rate would $310 have to be to invested to grow to $531.34 in 7 years? % (Round to the nearest whole percent.) c. At what annual rate would $47 have to be invested to grow to $611.99 in 21 years? 1( % (Round to the nearest whole percent.)