Hi Genome,
So, you ask a really good question. While you probably won’t get a definitive answer, I can give you some sense of what you would see in the process of scoring Q51.
Remember, no GMAT is the same as any other, meaning that the distribution of easy, medium, and hard questions is dependent on how you are doing on any particular exam. At the same time, since you would have to get almost all of the quant questions correct to score Q51, how your section would look is somewhat predictable.
Since the section starts off with medium-level questions, and you generally see harder questions as you answer correctly, you probably won't see any easy questions, though you might, in the beginning, see what you would consider some easier medium-level questions. As you progress through the section, you climb up in difficulty level, eventually seeing the most difficult questions that the quant section has to offer, but even once you get to a high level, not every question you see will be especially challenging. Along the way, you see some experimental questions, which can be of any difficulty level. So, for instance, right after your hardest question might be an easy experimental one.
Another factor that could affect how difficult the quant section feels for you is how the questions that you see match up with your strengths and weaknesses. Sometimes people feel that the easiest question (according to GMAC) that they see is difficult to answer because they are weak in that question's area of focus.
So, given all of the above, here is how a Q51 quant section tends to feel: For most people who are highly skilled in quant, the first few questions are pretty easy, unless one of those questions falls into a person's weaker areas. The questions get progressively harder but are not always especially hard. The difficulty level bounces around, and the person sees a mix of questions that seem to be medium-level, more difficult, and very difficult. As for how many of each level of difficulty a person sees, a good guess is perhaps 2 to 4 easier medium-level questions, 5 to 8 rather challenging, upper 700-level questions, and a bunch of questions that fall somewhere between those two types.
So, scoring Q51 does not take answering dozens of super-difficult questions, since you would see only a handful of the most difficult questions. That said, if you want to hit a Q51 on test day, you’ll need to dominate pretty much all questions that come your way, regardless of difficulty. So, your preparation for GMAT quant will have to be rather thorough. With that in mind, you may find it helpful to read this article about
how to improve your GMAT quant score.
Feel free to reach out with further questions.
Good luck!