Question

Wanda opened a savings account 20 years ago with a deposit of $3,150.37. The account has an interest rate of 4.1% compounded daily. How much interest has Wanda earned?

Answer 1

$\bf ~~~~~~ \stackrel{daily}{\textit{Continuously Compounding Interest Earned Amount}}\\\\ A=Pe^{rt}\qquad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{original amount deposited}\to& \ 3150.37\\ r=rate\to 4.1\%\to \frac{4.1}{100}\to &0.041\\ t=years\to &20 \end{cases} \\\\\\ A=3150.37e^{0.041\cdot 20}\implies A=3150.37e^{0.82}\implies A\approx 7152.91457$

how much interest is there?  well, A - 3150.37.