Question

In how much time will a sum of Rs. 1600 amount to Rs. 1852.20 at 5% per annum compound interest?

Answer 1

Given, 

Principal = Rs.1600 

Amount = Rs.1852.20 

Rate = 5 % per annum 

Let time = T years 

So,

A =  \({P}[({1}+\frac{R}{100})^T]\)

\(={1600}({1}+\frac{5}{100})^T\) = 185.20

\(=(\frac{21}{20})^T\) \(=\frac{1852.20}{1600}\) \(=\frac{9261}{8000}\) \(=(\frac{21}{20})^3\)

= T = 3 years 

Hence, 

Time = 3 years