Respuesta :

Let's set up a proportion

[tex] \frac{25}{125} \frac{x}{100} [/tex]

Solve for x:
25 x 100 = 2500
2500/125 = 20

She read 20% of the book.

Hope this helped! If you have any more questions or don't understand, please comment or DM me. :)
so the the formula for finding a percentage is 
pages read/ total pages × 100 = %
25/125×100=%
that gives you 
1/5×100=%
100/5=%
20=%
ans is 20%