Hi saviofernanz,
Yes, assuming that you know the overall content well enough - and you understand how to use Tactics, patterns and the little 'secrets' to the GMAT to your advantage - then you can answer all of the Quant questions in the time allotted. Thankfully, that is NOT a requirement to get into your first-choice School, so you have to be careful about confusing what you "want" to happen with what you "need" to happen.
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied? How many hours do you typically study each week?
2) What study materials have you used so far?
3) How have you scored on EACH of your CATs/mocks (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) What is your goal score?
5) When are you planning to take the GMAT?
6) When are you planning to apply to Business School?
7) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich