The compound interest on ₹18,000 at 7% per annum, compounded annually…

Formulas used here is :-

Amount = Principal + Interest

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

( 18000 + 1260 ) = 18000  [ 1 + \(\frac{7}{100}\) ]t

\(\frac{19260}{18000}\) = [  \(\frac{107}{100}\) ]t

\(\frac{107}{100}\) = [  \(\frac{107}{100}\) ]^t

So, t = 1 year