Having earned a bonus at his work, Rick placed the money in an investment earning 4.18% compounded monthly. He withdrew $343 at the end of every month for the next eight years, completely depleting the investment.
(a) What was the amount of the bonus?
(b) If he made all of the withdrawals as planned, how much interest was paid?
(c) If Rick made the same withdrawals, but the interest rate was 4.31% compounded monthly, by how much was the new investment amount increased or decreased?