Rs. 2100 is lent at compound interest of 5% per annum for 2 years. Find the amount after two years.

$$\eqalign{ & {\text{We}}\,{\text{can}}\,{\text{use}}\,{\text{formula}}\,{\text{of}}\,{\text{compound}}\,{\text{interest}} \cr & A = P \times {\left[ {1 + \left( {\frac{r}{{100}}} \right)} \right]^n} \cr & A = 2100 \times {\left[ {1 + \left( {\frac{5}{{100}}} \right)} \right]^2} \cr & A = 2100 \times {\left[ {\frac{{105}}{{100}}} \right]^2} \cr & A = \frac{{ {2100 \times 11025} }}{{10000}} \cr & {\text{Hence,}}\,{\text{Amount}}\,A = Rs.\,2315.25 \cr} $$