GMAT Strategy

As I mentioned briefly in my response to your PM, most people do think that our quant sections are a bit tougher than the real thing. There are two main reasons for this:

(1) The real test has experimentals and, the higher you are, the easier the experimentals might be for you. You don't get that kind of nice mental break on our test.
(2) Some of our problems are a bit too long / computation-intensive, where the real test usually has one "elegant" solution that allows you to avoid a decent portion of the intensive computation (assuming you know the "elegant" solution and can recognize when it's appropriate to use it, of course!)

Generally speaking, we're trying to prepare you for the timing issues that a lot of people have on this test - and the one thing that concerns me is that you're talking about running out of time on 9-10 questions. That's a lot - if that were to happen on the real test, it would kill your score. So, before you take your real test, you have to figure out how to handle things if you start to get behind, so that this doesn't happen on the real test.

That requires you to:
1) be aware of the timing as you move throughout the section, so that you know when you are too far behind ("too far" = more than about 2-3m behind on your timing benchmarks)
2) know what to do if you discover that you are too far behind

Right now, I don't know whether you're aware of your timing position as you move throughout the test, but I do know that you are not taking any actions to fix the problem when it occurs - you're just continuing and then running out of time. That's not the strategy you want for the real test.

First, you need to know what your timing benchmarks are. This is what I use for quant:
Q10: 55 min left
Q20: 35 min left
Q30: 15 min left

If I'm more than 2m off in either direction, then I'm messing up my time. If it's 2+ minutes higher than the expected time, I'm going too quickly and I need to slow myself down. If it's 2+ minutes lower than the expected time, I need to make up that time somehow - and that's the situation you're in.

So, how to get back on track? For each 2m that you're slow, you need to sacrifice one question. You're going to have to guess now - you have no choice about that. You do have a choice about when and how though: you can do what you're doing now and have to guess on that many questions at the end, or you can choose the hardest questions as you see them throughout the section, and you can guess on those. The latter is the better strategy (although the best strategy is not to put yourself in this position in the first place!).

So, the next time you read a question and think, "Ugh! What are they talking about?" - just pick your favorite letter and move on immediately. If you need to do it again, then do it again the next time you see a really hard question. Keep doing it till you're caught up.

Now, how to avoid that position in the first place? Well, you have to make sure that you're not going over 2.5m on quant. It's okay to go up to 3m maybe once or twice, but that's it. After that, even if you get the question right, you're just guaranteeing yourself something else wrong because you won't have enough time. (And you may not even have gotten that one right - any question that's going to take you 3+ is a question that's too hard for you and you're more likely to get it wrong than right!)

So, you need to learn about how long one minute is without looking at a watch or stopwatch. If you don't have one already, buy yourself a stopwatch with lap timing capability. When you go to do a set of problems, start the stopwatch but turn it over so you can't see the time. Every time you think one minute has gone by, push the lap button. When you're done, see how good you were - and whether you tend to over or underestimate. Get yourself to the point where you're within 15 seconds either way on a regular basis (that is, you can generally predict between 45 sec and 1min 15 sec).

Now, how do you use that when doing problems? If you're not on track by one minute*, make an educated guess and move on. (The general idea is that if you're not on track by the halfway mark, you're unlikely to figure out what's holding you back AND have time to do the whole problem in the 1 min you have left.)

* For SC, 1min is well beyond the half-way mark (we're supposed to average about 1m15s here), but you can almost always eliminate at least some choices on SC in that timeframe. Once you've got that "I'm around the 1min mark and I'm struggling" feeling, go through any remaining choices ONCE more. Pick one. Move on.

Great job on GMATPrep, by the way!! Make sure to do future tests under full official conditions, including the essays - that's the only way to make sure your score isn't artificially inflated by some advantage that you'd never get on the real test.