Person A has an IQ of 90, while person B has an IQ of 120. Give them some various educational books, and assuming they put the same amount of time and effort into reading those books and trying to understand them, it would make sense to me that person B would have learned and understood more.
That is probably true for a lot of people, possibly even most people, (but I doubt it) but some people would not follow this standard. Everyone has their own strengths and weaknesses. A person who did well on an IQ test may have just as hard of a time trying to read the books as the other person, but may be great at rearranging shapes for some reason and doing whatever it is you are supposed to do w/ them (I took the test once, but honestly can't remember:p ). Really, a complete idiot could pass one of those things. Or a really smart person could fail it b/c they are not good test takers.