Question

What should be invested for $4$ years at $9\%$ per year to earn $Rs.108$ simple interest?

Answer 1

Given, time $\left(T\right)=4$ years.
Rate of interest $\left(R\right)=9\%$
Interest amount $\left(I\right)=Rs.108$
Since, Simple interest$\left(I\right)=\frac{PTR}{100}$, Where $P$ is principal amount.
Substitute given values, we get
$108=\frac{P\times 4\times 9}{100}$
$P=\frac{108}{36}\times 100$
$=3\times 100$
$\therefore P=Rs.300$
Hence, $Rs.300$ should invested.