(Compound value solving for r) At what annual rate would the following have to be invested? a. $510 to grow to $1,148.62 in 12 years b. $280 to grow to $479.87 in 7 years c. $51 to grow to $551.00 in 21 years d. $204 to grow to $247.96 in 4 years a. At what annual rate would $510 have to be invested to grow to $1,148.62 in 12 years? % (Round to the nearest whole percent.) b. At what annual rate would $280 have to be to invested to grow to $479.92 in 7 years? % (Round to the nearest whole percent.) c. At what annual rate would $51 have to be invested to grow to $551.00 in 21 years? % (Round to the nearest whole percent.) d. At what annual rate would $204 have to be invested to grow to $247.96 in 4 years? % (Round to the nearest whole percent.)