₹3600 becomes ₹4900 in 2 years when kept at compound interest (compounded anaually). What is the rate of interest per annum?

$16\frac{2}{3}\%$

The Formula that we used here is -

Amount = P$(1 \;+\; \frac{R}{100})^t$

4900 = 3600 [ 1 + \(\frac{R}{100}\)]²

\(\frac{4900}{3600}\) = [ 1 + \(\frac{R}{100}\)]²

(\(\frac{7}{6}\))²  = [ 1 + \(\frac{R}{100}\)]²

\(\frac{7}{6}\) = 1 + \(\frac{R}{100}\)

\(\frac{R}{100}\) = \(\frac{7}{6}\) - 1

\(\frac{R}{100}\) = \(\frac{1}{6}\)

R = 16\(\frac{2}{3}\)%