Keiko is looking at the following investment choices and wants to know what interest rate each choice produces.
a. Invest $400 and receive $786.86 in ten years.
b. Invest $3,000 and receive $10,927.45 in fifteen years.
c. Invest $31,180.47 and receive $100,000 in twenty years.
d. Invest $31,327.88 and receive $1,000,000 in forty-five years.