Interest rate. Two mutual fund managers, Martha and David, have been discussing whose fund is the top performer. Martha states that investors bought shares in her mutual fund 10 years ago for $30.00, and those shares are now worth $62.00. David states that investors bought shares in his mutual fund 7 years ago for only $2.70, and they are now worth $8.20. Which mutual fund manager had the higher growth rate for the management period? Should this comparison be made over different management periods? Why or why not