Question

How long will it take 5000 to double in an account that pays 5.6% simple interest

Answer 1

So... doubling 5000 is just 10,000, thus

$\bf \qquad \textit{Simple Interest Earned Amount}\\\\ A=P(1+rt)\qquad \begin{cases} A=\textit{accumulated amount}\to &\ 10,000\\ P=\textit{original amount deposited}\to& \ 5,000\\ r=rate\to 5.6\%\to \frac{5.6}{100}\to &0.056\\ t=years \end{cases} \\\\\\ 10000=5000(1+0.056t)\implies \cfrac{10000}{5000}=1+0.056t \\\\\\ 2=1+0.056t\implies 1=0.056t\implies \cfrac{1}{0.056}=t$