The expression for Simple Interest is :
[tex]\text{Simple Interest = }\frac{\text{ Principal AMount}\times Time\text{ }\times Rate\text{ of Interest}}{100}[/tex]Given that Principal amount = $900
Time period = 2 years
Simple Interest = $18
Substitute the value and solve for RAte of interest
[tex]\begin{gathered} \text{Simple Interest = }\frac{\text{ Principal AMount}\times Time\text{ }\times Rate\text{ of Interest}}{100} \\ 18=\frac{900\times2\times R}{100} \\ R=\frac{18\times100}{900\times2} \\ R=1 \\ \text{ Rate of interest = 1 percent} \end{gathered}[/tex]Answer : Interest Rate = 1%
