The compound interest on Rs. 30000 at 7% per annum is Rs. 4347. The period (in years) is = ?

Solution (By Examveda Team)

$$\eqalign{ & {\text{Amount = Rs}}{\text{. }}\left( {30000 - 4347} \right) \cr & {\text{Amount = Rs}}{\text{. }} 34347 \cr & {\text{Let the time be }}n{\text{ years}} \cr & {\text{Then,}} \cr & {\text{30000}}{\left( {1 + \frac{7}{{100}}} \right)^n} = 34347 \cr & \Leftrightarrow {\left( {\frac{{107}}{{100}}} \right)^n} = \frac{{34347}}{{30000}} \cr & \Leftrightarrow {\left( {\frac{{107}}{{100}}} \right)^n} = \frac{{11449}}{{10000}} = {\left( {\frac{{107}}{{100}}} \right)^2} \cr & \therefore n = {\text{ 2 years}} \cr} $$