Question

Find the rate percent per annum, if Rs. 2000 amount to Rs. 2315.25 in an year and a half, interest being compounded six monthly.

Answer 1

Given, 

Principal = Rs.2000 

Amount = Rs.2315.25 

Time \(={1}\frac{1}{2}\) years \(=\frac{3}{2}\) years

Let rate = R % per annum

A \(={P}[({1}+\frac{R}{100})^T]\)

\(={2000}[({1}+\frac{R}{100})^{\frac{3}{2}}]\) = 2315.25

\(=({1}+\frac{R}{100})^{\frac{3}{2}}\) = 1.1576

\(={1}+\frac{R}{100}\) = 1.1025

\(=\frac{R}{100}\) = 0.1025

= R = 10.25%

Hence , 

Rate = 10.25%