How much simple interest does $2,560 earn in 17 months at a rate of$1 $\frac{1} {8}$ %?$ Round to the nearest cent.

We have to calculate how much simple interest does $2,560$ earn in 17 months at a rate of $1\dfrac{1}{8}\%$ . We have to calculate interest using by equation,

$$\begin{align*} I=Ptr \end{align*}$$

where is $I$ interest, $r$ is rate, and $P$ is principal. In our case $r=1\dfrac{1}{8}=1.125\%=0.01125$,$P=2560$ USD, and $t=17\text{months}=\dfrac{17}{12}$ so we calculate interest,

$$\begin{align*} I=2560 \cdot 0.01125\cdot \dfrac{17}{12}=28.80\cdot \dfrac{17}{12}=40.8\,\,\text{USD}. \end{align*}$$