Hi souvonik2k,
Based on your prior CAT Scores, it's possible that you just had a 'bad day' when you took this CAT. That having been said, a Q39 means that you would have made a lot of little mistakes as you worked through the Quant section AND that you missed out on lots of 'strategy-based' points. Given the 'swing' in your Quant Scaled Scores, I have a few questions about how you have taken your CATs:
1) How did you score on each of your CATs (including the Quant and Verbal Scaled Scores for each)?
2) Did you take the ENTIRE CAT each time (including the Essay and IR sections)?
3) Did you take them at home?
4) Did you take them at the same time of day as when you plan to take your Official GMAT?
5) Did you ever do ANYTHING during your CATs that you couldn't do on Test Day (pause the CAT, skip sections, take longer breaks, etc.)?
6) Did you ever take a CAT more than once? Had you seen any of the questions BEFORE?
GMAT assassins aren't born, they're made,
Rich