Haha, they are not kidding, the quiz is so hard! (I suspect that some answers that are supposed to be correct are in fact wrong!) Nevertheless, I tried both of the quiz and managed to get 2 free books as they promised.
Hee hee, let's see if they really gives out the book in a weeks time :) If they really sent it, I would have won a cool $45.80 worth of books :P I quite like the Professor Sage's series of books as it catered to local context, so I do hope I'll get both of them for free :P
Go try it, no harm right?