Question

Lane invests $7,000, at 7% interest, compounded annually for 22 years. Calculate the compound interest for his investment.

Answer 1

$\bf ~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+\frac{r}{n}\right)^{nt} \quad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{original amount deposited}\dotfill &\ 7000\\ r=rate\to 7\%\to \frac{7}{100}\dotfill &0.07\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \textit{annually, thus once} \end{array}\dotfill &1\\ t=years\dotfill &22 \end{cases} \\\\\\ A=7000\left(1+\frac{0.07}{1}\right)^{1\cdot 22}\implies A=7000(1.07)^{22}\implies A\approx 31012.81$