4-99. You deposit $2,500 at the end of the year (k = 0) into an account that pays interest at a rate of 7% compounded annually. Two years after your deposit, the savings account interest rate changes to 12% nominal interest compounded monthly. Five years after your deposit, the savings account again changes its interest rate; this time the interest rate becomes 8% nominal interest compounded quarterly. Nine years after your deposit, the saving account changes its rate once more to 6% compounded annually.

a. How much money should be in the savings account 15 years after the initial deposit, assuming no further changes in the account’s interest rate?

b. What interest rate, compounded annually, is equivalent to the interest pattern of the saving account in Part

(a) over the entire 15-year period?