First, let's talk about what a 600 means...A 600 means the 66th percentile, so the number 600 does not have any independent meaning it is just a way for the people that write the GMAT to say 66th percentile.
But 66 percent of what? The way that you are compared to other test takers is by adding your scaled scores together. That is the q ___ and v __ that you mentioned. They stand for qualitative and verbal. The official GMAT practice test that you took at mba.com does give you those scaled scores but only once and only briefly so it is very easy to overlook.
There are many ways that you could have earned a 600. If your scaled scores were nearly equal, then your overall percentage is usually higher. So you could for example, score around the 55th percentile on the quantitative and the verbal as compared to your overall score.
Or, one of your scores could be significantly higher than the other. On the GMAT, as you get well above the 50% percentile, the verbal score actually has more weight than the quantitative. So if verbal is your strength, congratulations! For example, I know of someone who scored in the 99th percentile verbal, 74th percentile quantitative, and 99th overall.
Basically, you want to do well in both areas, quantitative and verbal. But if you could really excel in one area or the other, make it verbal. Next time you take a GMAT prep test from mba.com, pay very careful attention at the end of the test and you will see those scaled scores.
Good Luck!
David
