On a certain sum the interest paid after $3\mathrm{years}\mathrm{is}450\mathrm{at}5\%\mathrm{rate}\mathrm{of}\mathrm{interest}\mathrm{per}\mathrm{annum}$. Find the sum.

Find the sum:

As it is Given that,

On a certain sum, the interest is paid after $3\mathrm{years}\mathrm{is}450\mathrm{at}5\%\mathrm{rate}\mathrm{of}\mathrm{interest}\mathrm{per}\mathrm{annum}$.

Here, $\mathrm{Rate}=5\%,\mathrm{Time}=3\mathrm{years},\mathrm{Intrest}=\mathrm{Rs}450$

We know that,

$$\begin{gathered} \mathrm{Intrest}=\frac{\mathrm{Principal}\times \mathrm{Rate}\times \mathrm{Time}}{100} \\ \Rightarrow 450=\frac{\mathrm{P}\times 5\times 3}{100} \\ \Rightarrow 450\times 100=15\times \mathrm{P} \\ \Rightarrow \mathrm{P}=\frac{45000}{15}=3000 \end{gathered}$$

Hence, the sum i.e. Principal is $Rs3000$.