Respuestas al mensaje #10

Okay, NOW I've figured it out. The result was 48 after solving my algebraic fractions. Thank you.

I had to write down the equation because I can't juggle it all in my head at once, but I got the right answer. Maybe I'm retarded and was never...

That's how I solved it. Doesn't need algebra or anything, only the knowledge that 30 pages constitutes 5/8 of the book.