What rate gives Rs. $280$ as interest on a sum of Rs. $56000$ in $2$ years?

Given, $I=$ Rs. $280$

$P=$ Rs. $56,000$

$T=2$ years

$R=?$

Now,

$I=\frac{PRT}{100}$

$\Rightarrow 280=\frac{56,000\times R\times 2}{100}$

$\Rightarrow 280=560\times 2\times R$

$\Rightarrow R=\frac{280}{560\times 2}$

$\Rightarrow R=\frac{14}{56}$

$\Rightarrow R=\frac{7}{28}$

$\Rightarrow R=\frac{1}{4}$

$\therefore R=0.25$

$\therefore$ Rate of interest $=0.25$ % per annum.