Bank A pays 6% simple interest annually. Bank B pays 5.9% interest, with annual compounding. Bank C pays 5.8% interest, with monthly compounding.
a. How long will it take for your money to double in each of the three banks? Please state your answers in years, rounded to the nearest tenth of a year (e.g., 6.3 years).
b. In one or two sentences, what does your answer to part A illustrate about compound interest?