Two years ago, Ben borrowed $150 from his brother to buy a CD player. He agreed to pay $15 in interest. What is the simple annual interest rate for this loan?

[tex]\bf \qquad \textit{Simple Interest Earned}\\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\to &\$15\\ P=\textit{original amount deposited}\to& \$150\\ r=rate\to r\%\to \frac{r}{100}\\ t=years\to &2 \end{cases} \\\\\\ 15=150\cdot r\cdot 2\implies \cfrac{15}{150\cdot 2}=r\implies \cfrac{1}{10}=r \\\\\\ r\cdot 100\implies \stackrel{\%}{10}[/tex]