Question

Catelyn invested $7000 in an account that earns 5.6% interest, compounded annually. The formula for compound interest is A(t) = P(1 + i)^t. How much did Catelyn have in the account after 4 years?

Answer 1

$\bf ~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+\frac{r}{n}\right)^{nt} \quad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{original amount deposited}\to &\ 7000\\ r=rate\to 5.6\%\to \frac{5.6}{100}\to &0.056\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \textit{annually, thus once} \end{array}\to &1\\ t=years\to &4 \end{cases} \\\\\\ A=7000\left(1+\frac{0.056}{1}\right)^{1\cdot 4}\implies A(t)=7000(1.056)^4\implies A\approx 8704.698$

Answer 2

Exactly as my friend said!
A smartphone calculator nowadays is quite helpful. In the future you just ca just type for ex. 7000 + 5,6 and hit the % buton them equal (the dirst year total with interest) than + 5,6 and again hit the % button and than = and so on 4 times and you will have the answer from previous answer. Hope it helps