In $1975$, interest rates were $7.98 \%$ and the rate of inflation was $12.26 \%$ in the United States. What was the real interest rate in $1975$? How would the purchasing power of your savings have changed over the year?

Find the monthly interest rate $r$ when

$$A P R=13.2$$

To make CDs look more attractive than they really are, some banks advertise that their rates are higher than their competitors’ rates; however, the fine print says that the rate is a simple interest rate. If a person deposits $10,000 at 10% per year simple interest, what compound interest rate would yield the same amount of money in 3 years?

Graph the simple interest earned on $950 at an annual rate of 4.2%.

In this exercise, use the add-on method of calculating interest to find the total interest and the monthly payment.

Suppose that $20,000 is invested at continuous rate r and grows to$81,104 in 28 years. Find the interest rate r.

Work the following applied problem.

Which of these 20-year zero-coupon bonds will be worth more at maturity: one that sells for $4510, with a 6.1% interest rate, or one that sells for$5809, with a 4.8% interest rate?

Reggie invests $12,000, part at 7% annual interest and part at 8.5% annual interest. How much is invested at each rate if Reggie’s total annual interest is$900?

In this exercise, use the add-on method of calculating interest to find the total interest and the monthly payment.

What happens to the present value of an annuity as the interest rate increases?

Find the time required for a $1000 investment to (a) double at interest rate r, compounded continuously, and (b) triple at interest rate r, compounded continuously. Round your results to two decimal places.$r = 6%$

In this exercise, use the add-on method of calculating interest to find the total interest and the monthly payment.

What happens to the present value of an annuity as the interest rate increases?

Solve for the unknown interest rate in each of the following: