Given,
Principal = Rs.640
Amount = Rs.774.40
Time = 2 years
Let rate = R%
So
A = \({P}[({1}+\frac{R}{100})^T]\)
\(={640}[({1}+\frac{R}{100})^2]\) = 774.40
\(=({1}+\frac{R}{100})^2]\) \(=\frac{774.40}{640}\)
\(=\frac{484}{400}\) \(=(\frac{22}{20})^2\)
\(={1}+\frac{R}{100}\) \(=\frac{22}{20}\)
\(=\frac{R}{100}\) \(=\frac{22}{20}\) = 1 = \(\frac{2}{20}\)
= R \(=\frac{2\times100}{20}\) = 10% per annum
Hence,
Rate = 10% per annum
