For an amount, simple interest at the rate of interest of 12% per annum for 6 years is Rs 25920. What will be the compound interest (in Rs) on same amount at the rate of interest of 8% per annum compounding annually for 2 years?

Let the principal amount = Rs. $$100x$$

Rate of interest = 12% and time period =6 years

=> $$S.I. = \frac{P \times r \times t}{100}$$

=> $$\frac{100\times12\times6}{100}=25920$$

=> $$72x=25920$$

=> $$x=\frac{25920}{72}=360$$

Thus, amount = $$100\times360=Rs.$$ $$36000$$

$$\therefore$$ Compound interest at the rate of interest of 8% per annum compounding annually for 2 years

= $$P[(1+\frac{r}{100})^t-1]$$

= $$36000[(1+\frac{8}{100})^2-1]$$

= $$36000[(\frac{27}{25})^2-1]$$

= $$36000(\frac{729-625}{625})$$

= $$57.6\times104=Rs.$$ $$5990.4$$

=> Ans - (D)