If the amount received at the end of 2nd and 3rd year at Compound Interest on a certain Principal is Rs 1,800, and Rs 1,926 respectively, what is the rate of interest?

Amount received at the end of 2nd yr = P$$(1+\frac{R}{100})^{2}$$ = 1800 -------(1)

Amount received at the end of 3rd yr = P$$(1+\frac{R}{100})^{3}$$ = 1926 -------(2)

divide (2) with (1)

$$\Rightarrow\frac{P(1+\frac{R}{100})^{3}}{P(1+\frac{R}{100})^{2}} = \frac{1926}{1800}$$

$$\Rightarrow 1+\frac{R}{100}$$ = $$\frac{1926}{1800}$$

$$\Rightarrow \frac{R}{100}$$ = $$\frac{1926}{1800}-1$$

$$\Rightarrow \frac{R}{100}$$ = $$\frac{1926-1800}{1800}$$

$$\Rightarrow \frac{R}{100}$$ = $$\frac{126}{1800}$$

$$\Rightarrow \frac{R}{100}$$ = $$\frac{7}{100}$$

$$\Rightarrow R = 7$$%

So the answer is option B.