It's actually kind of complicated
The way that GMAT scores is very different from SAT. The score is depend on the level of difficulty of the questions given. So for instance, let's say that you got 5 questions wrong, but the ones that you got right are all easy questions, then your raw score might be lower. But, if you got 10 questions wrong but the ones that you got right are all difficult questions, then your raw score would be higher.
The trick is to get all the first 10 questions right and save the wrong answers for the last few --that can make your score higher.
To tell you the truth, the scoring system is coordinated by computers, not by humans. So, I don't think there is anyone in the world who can tell you exactly what score that you are going to get just based on how much you got wrong. But no matter what you do, keep on practicing! | 
