Got it - okay, I understand.
It makes sense (obviously! :) that you'd do better on lower-level questions. Here's the thing: sometimes studying lower-level questions actually helps you to learn to do better on higher-level ones. For instance, a lower-level question in the same area might have aspects in common with a higher level one - so studying the lower-level one (figuring out additional shortcuts, or really understanding why it works the way it does) can actually then help you on similar higher-level ones.
Also, the trend is only a trend on average - you'll have times that you do get lower-level question wrongs (maybe more consistently in certain areas of weakness) and so you want to make sure that you're still studying those areas.
Of course, you do also want to study the higher level ones; you just don't want to limit yourself to those, that's all.
I could solve almost all of them correctly without knowing the answer if I gave myself unlimited time.
Sadly, we'll never have unlimited time. It's great that you've realized part of the problem is not recognizing what to do / what the problem is testing. One of the ways you get better at that... is going back over those easier problems again and asking yourself very specific questions. HOW did I know that this (easier for me) problem was testing XYZ? What are the specific clues? Does this other, harder problem that I didn't recognize have ANY similarities with other easier questions that I did know how to do? What are those similarities? How can I use that knowledge to get "into" the harder problem? Etc.
Use the easier ones to really pick apart your process / knowledge (and also to look for shortcuts and guessing methods), then apply that knowledge to the ones that are harder for you.
So now you know my answer to your last question right? Go study some of the easier-but-not-super-easy problems. Here's a guide to the kinds of questions to ask yourself:
http://www.manhattangmat.com/articles/a ... roblem.cfmWhen doing a set of problems, probably the first 20 to 40 in OG are going to be mostly too easy for you - and probably the last 40 or so are going to be too hard. So pick from the group in between, but do hit a range (of easier to harder) within that.