Hola
Note, that if \( n \) is the number of pages of a book, then the sum of the page number is:
\( \dfrac{n(n+1)}{2} \)
So, you know that:
\( n(n+1)\geq 2\cdot 15000 \)
on the other hand if \( x,x+1 \) are the numer pages of the torn leaf, then:
\( x+1\leq n \) and \( \dfrac{n(n+1)}{2}-(2x+1)=15000 \)
Play with this.
Best regards.
