GMAT Strategy

Two inquiries of mine:

a) I'm going through the Date Sufficiency right now (I'm at #110 out of 174 I believe) and I keep stumbling through a lot of these problems. Is it normal to have difficulties with some of the OG material? Is this a bad warning sign? Or should it just be assumed that the latter problems are difficult for most students and that I have nothing to worry about so long as I study the explanations closely?

b) In your opinion, is the OG representative of just about every math topic you can possibly see on the GMAT? Obviously the questions will be re-worded and such, but are the concepts and logical reasoning behind the problem sets basically what you'll see on test day? Is there any major problem type or theory that is left out of the OG from what you can see?


Thanks in advance!

a) OG questions are ordered by difficulty level in ascending order (the trend is not linear but generally easier to harder). It is therefore to be expected that depending on your abilility level, you will encounter more and more difficulties as you get deeper and deeper into the section.

b) The OG questions have the same flavor, reasoning, topics, etc... as real gmat questions for one simple reason: OG questions ARE real GMAT questions that have been retired from the test and made available for publication