Could someone who has taken the GMAT exam please comment about the difficulty of the math questions in the real test as compared to the math questions that appear in the OG book.

Are the OG math questions easier, about the same, or harder than those that appear in the real test.

I thought the math section would be my strong area considering that I was an engineering major from a respectable univ, had got mostly As in college math courses.....but now I getting about 30% questions wrong the from the Data Sufficiency section of the OG. To say the least, I'm very depressed.

I plan to go through every question from the OG before taking any Practice Tests.....but just to my curiosity sake....a score of X% questions correct translates to what GMAT score? For example, the OG states that the Quant section will contain 37 questions. If I get 30 right what will be my GMAT score ?

thanks,

EM

(I'm new to this forum....sorry if it's a repeat question )