### Home > CCAA > Chapter 9 Unit 8 > Lesson CC2: 9.1.1 > Problem9-12

9-12.

Sasha saved $\850$ from her summer job last summer. She put it in an account that earns simple interest each month. After $9$ months, her account is worth $\1003$. What percent interest did she earn each month?

Find the amount of money Sasha gained over the $9$ months (the interest).

$\1003-\850=\153$

Use the equation $I=Prt$, where $I$ is the interest, $P$ is the principle (original amount she had), $r$ is the rate (percent interest per month), and $t$ is the time (number of months that have passed).

$153=(850)$ $r(9)$Solve for $r$.

$r=\frac{153}{850(9)}$

$2\%$ interest