Answer :

[tex]0.6=\dfrac{6}{10}=\dfrac{3}{5}\\ 0.025=\dfrac{25}{1000}=\dfrac{1}{40}[/tex]
[tex]a)\ 0.\underbrace{6}_{tenth}=\frac{6}{10}=\frac{6:2}{10:2}=\frac{3}{5}\Rightarrow\boxed{0.6=\frac{3}{5}}\\\\\\b)\ 0.\underbrace{025}_{thousandth}=\frac{25}{1000}=\frac{25:25}{1000:25}=\frac{1}{40}\Rightarrow\boxed{0.25=\frac{1}{40}}[/tex]