When I passed through the paper sift stage of my Police application, I ordered this book on the recommendation from a close friend before going to Centrex. As other people have mentioned, the questions are not that difficult. But for people like myself who had not done any maths since high school, it brought me back up to what will get a pass or fail - SPEED. In the PIRT you will have to race through the numerical questions as quickly as possible to complete the test. So the quicker you get into practice the better you will perform on the day. The book contains sample questions similar to the ones on the test so you can't go wrong.
On the verbal logical reasoning, again, it provides examples of past questions but speed is not the agenda here. Its all about judgement and even though I had an issue with a couple of answers, the practice was justified in preparation for the day itself. Use this book to prepare and get up to speed. Even a couple of marks will make all the difference when your feedback arrives in the post a few days later!! Good Luck.