Let the first number be x and second number be y
If 25% of x is subtracted from y i.e. $(y - \frac{{25}}{{100}}x,)$ then y becomes $(\frac{5}{6}y)$
i.e. $(y - \frac{{25}}{{100}}x = \;\frac{5}{6}y)$
$(\Rightarrow y - \frac{5}{6}y = \frac{x}{4})$
$(\Rightarrow \frac{y}{6} = \frac{x}{4})$
$(\Rightarrow \frac{x}{y} = \frac{2}{3})$