Either way the answer is in the book... whether you PRed the answer in answer form or only the information section. If you let your whole mind work it out, it will... with or without 'seeing' the answer section. In some books you see the answer and still don't understand how you get that answer. The mind must have worked it out if it is able to accept and present to the concious mind the answer as the correct one. It's pretty common to have someone read an answer and say "I don't get it."
It is probable that the mind works out the answer faster as a result of coming across the answer section... but if it doesn't make sense on the neural pathways then it won't present that answer as correct. The answers are often give so that you can work the solution backwards. While it may make the process faster by having photoread the answer I don't think you would lose anything by it because your inner mind still works it out creating neural pathways to solve problems similar to that faster and faster in the future.
Alex
