Given,
Principal = Rs.64000
Rate of interest = 5% per annum \(=\frac{5}{2}\text%\) half yearly
Time \({1}\frac{1}{2}\) years
\(=\frac{2}{2}\times{2}\) = 3 half years
Hence,
Compound interest \(={P}[({1}+\frac{R}{100})^T-{1}]\)
\(={64000}[({1}+\frac{5}{2\times100})^3-{1}]\)
\(={64000}[(\frac{41}{40})^3-{1}]\)
\(={64000}\times\frac{4921}{64000}\) Rs. 4921
So, interest paid by Abha = Rs.4921