Given :
A = 25000
P = 20000
r % = 9.6 % = 0.096
n = 12
To Find :
The time taken say t.
Solution :
We know, compound interest is given by :
[tex]A=P(1+\dfrac{r}{n})^{n.t}[/tex]
Taking log both sides :
[tex]A=P(1+\dfrac{r}{n})^{n.t}\\\\log\ \dfrac{A}{P}= n.t\times log( 1+\dfrac{r}{n})\\\\t =\dfrac{1}{n}\times \dfrac{log\ \dfrac{A}{P}}{log(1+\dfrac{r}{n})}\\\\\\t=\dfrac{1}{12}\times \dfrac{log\ \dfrac{25000}{20000}}{log(1+\dfrac{0.096}{12})}\\\\\\t=2.33\ years[/tex]
Hence, this is the required solution.
