Question

matthew invested $5000 in an account that earns 3.8% interest . how much did matthew have in his account after 3 years

Answer 1

the assumption being "simple interest" rate of 3.8%, as opposed to "compound interest".

$\bf ~~~~~~ \textit{Simple Interest Earned Amount} \\\\ A=P(1+rt)\qquad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{original amount deposited}\dotfill & \ 5000\\ r=rate\to 3.8\%\to \frac{3.8}{100}\dotfill &0.038\\ t=years\dotfill &3 \end{cases} \\\\\\ A=5000[1+(0.038)(3)]\implies A=5000(1.114)\implies A=5570$