### Home > PC3 > Chapter 5 > Lesson 5.1.2 > Problem5-20

5-20.

​Use your knowledge of compound interest to complete the parts below.

1. How much money will you have after $5$ years if $\1050$ is invested at $7\%$ annual interest, compounded quarterly?

$1050\left(1+\frac{0.07}{4}\right)^{(4)(5)}$

2. How long will it take an account to have $\11,000$ if $\5000$ is invested at $8.2\%$ annual interest, compounded monthly?

$5000 \left( 1+\frac{0.082}{12} \right)^ {(10)(12)}$

3. Write an equation for the amount of money you will have after $t$ years if $P$ dollars are invested at $r\%$ annual interest, compounded $n$ times per year.

$1. \ \ P\text{ is the initial amount.}$

$2. \ \ 1 + \frac{r}{100n}\text{ is the multiplier.}$

$3.\ \ nt \text{ is the number of compoundings.}$