The question here is poorly phrased, since they failed to describe if it were 2/5 of a page of the same book, or 2/5 of the book's pages. Attempting it in the wrong direction will lead to a different answer. You might be advised to attempt a less ambiguous question for practice instead. Should you see this in an examination, feel free to clarify with an invigilator / your teachers :)

Noted. Thanks for you info