so, the bank is asking for 1000, and in 10 years they'd be doubled, meaning they'd be 2000, then,
[tex]\bf ~~~~~~ \textit{Simple Interest Earned Amount}\\\\
A=P(1+rt)\qquad
\begin{cases}
A=\textit{accumulated amount}\to &\$2000\\
P=\textit{original amount deposited}\to& \$1000\\
r=rate\to r\%\to \frac{r}{100}\\
t=years\to &10
\end{cases}
\\\\\\
2000=1000(1+r\cdot 10)\implies \cfrac{2000}{1000}=1+10r\implies 2=1+10r
\\\\\\
1=10r\implies \cfrac{1}{10}=r\implies r\%=100\cdot \cfrac{1}{10}\implies r=\stackrel{\%}{10}[/tex]
