John buys a stereo system for 640 dollars. He agrees to pay 32 dollars a month for 2 years. Assuming that interest is compounded monthly, what interest rate is he paying?

In a particular bank account, money doubles in 10 years. What is the annual interest rate compounded continuously?

if you have an interest rate subsidy from a home builder or real estate developer, you have a

A deposit of $400 is made in an account that earns interest at an annual rate of 2.5%. How long will it take for the balance to double when the interest is compounded (a) annually, (b) monthly, (c) daily, and (d) continuously?

$$A = P ( 1 + r ) ^ { n }$$

gives amount A in an account after n years for an initial investment P that earns interest at an annual rate r. How long will it take for $250 to increase to$500 at 4% annual interest?

A loan of $\$ 2,500$ was repaid at the end of $10$ months with a check for $\$ 2,812.50$. What annual rate of interest was charged?

An investment account with an annual interest rate of $7 \%$ was opened with an initial deposit of $\$ 4,000$ Compare the values of the account after $9$ years when the interest is compounded annually, quarterly, monthly, and continuously.

Each percent is an annual interest rate. In the formula $y=a \cdot b^x$, what value would you use for $b$?

$$0.5 \%$$

Compound Interest Complete the table for the time $t$ (in years) necessary for $P$ dollars to triple if interest is compounded annually at rate $r$.

What is the future value of $3,100 in 17 years assuming an interest rate of 8.4 percent compounded semiannually?

Find the present value of the given future amount; use simple interest.

A 6-month $10,000 T-bill sold at a 4% discount. Find the actual rate of interest paid by the Treasury.

An investment account with an annual interest rate of $7 \%$ was opened with an initial deposit of $\$ 4,000$ Compare the values of the account after $9$ years when the interest is compounded annually, quarterly, monthly, and continuously.

Determine the present value of $750,000 to be received in three years, using an interest rate of 12%, compounded annually.

Toni invested $\$ 250$ in a savings account for 4 years. The total interest earned on the investment was $\$ 125$. What was the interest rate on the account?

(F) $3.125 \%$

(G) $12.5 \%$

(H) $125 \%$

(J) $1125 \%$