My experience of the practice gmatprep
Q51 is the max you can get on the gmatprep, but it is unclear how the program computes the score. I have scored 51 with 3 wrong questions, but typically, 2 wrong questions = 51, 3 wrong questions = 50. I have also managed a perfect score and still it was a 51. For these tests, I usually just skipped the verbal by just randomly guessing, and get 6-7 verbal questions correct. The Q51 scores were due to me having familiarization with some of the questions.
I also took the test and forced myself to complete the verbal section. I got a Q51, with a V33, a total of only 700. I just took the complete practice test again yesterday, but the surprising part is that I got 6 (that is right, 6) math questions wrong, including the very first question, and still got a Q51. I got V42 for a total score of 760.
My guess is that the verbal score does effect the lienency of the computation of the math score (or vice versa?).