Question

Valentina puts $400.00 into an account to use for school expenses. The account earns 6% interest, compounded annually. How much will be in the account after 9 years?

Answer 1

`~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+(r)/(n)\right)^(nt) \quad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{original amount deposited}\dotfill &\$400\\ r=rate\to 6\%\to (6)/(100)\dotfill &0.06\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \textit{annually, thus once} \end{array}\dotfill &1\\ t=years\dotfill &9 \end{cases} \\\\\\ A = 400\left(1+(0.06)/(1)\right)^(1\cdot 9) \implies A = 400( 1.06)^(9)\implies A \approx 675.79`