the intuitive way to read this is  > (a book costs $1) plus half its price. this makes it appear in the human mind that the book costs $1, and then half of that is added again, leading to most people who read the question to answer $1.5 and then move on. while the intended way to read it is > a book costs ($1 plus half its price). which is not intuitive, as most humans simply do not process information presented like that in such a way.
Germany