There's a real chasm between Q49 and Q50: in my experience, Q49 seems to allow a whole heap of questions wrong, but Q50 seems to allow at most three or four wrong (no matter where they occur). I've had a lot of students who were getting at most 60% of tough (GMAT-level, not weekly challenge level or anything) math questions right in practice who scored Q49 on the real test, including one just this past weekend, but the only students who get Q50 or Q51 are the type who get 90% of daily/weekly challenge (i.e. harder than the GMAT, though using the same tricks) problems right, and in two minutes each, to boot.

This makes sense given the difference in percentiles between the two scores, but the value of a Q50 is much lower than you'd think - a Q49 is excellent and more than enough to give you a great GMAT score (700, 750, whatever) depending on your verbal. As my buddy Brian@VeritasPrep says, on the quant section, your floor is more important than your ceiling: the GMAT doesn't really reward you much for breaking Q47 or Q48, so once you're there, concentrate on your verbal.

Thank you guys!
At the begining, when I saw those 14 questions that I failed, I felt depressed. But surprised when I noticed that my score was 49 in Quant.
My doubt now is when I should stop. When I could say: Ok, it's enough. I am ready. I would be fine with a 49 because I think that a 50 won't increase my overall score, right?
In this sense, when could I say that I am ready for a 49?

PS. I expect a 40-42 in Verbal.