Knewton free test...got 600 :(

I do not think that Knewton's CATs are completely off. Also this is not of importance either.

If you do not have much time there is only one thing to do. PRACTICE. If you don't have it already get the Official Guide and do all the hard questions. You can buy a Kindle version within a few seconds. If you have an iPhone I would really recommend GMATClub's paid application "GMAT Toolkit" although I found its questions unreasonably hard, its great to use in combination with the OG through its OG Tracker feature. You can time your answers and keep track of what you are doing. Since you don't have time, jump to the hard ones immediately and do ALL of them. For every mistake make sure you understand the theory very well and for every question you spend more than 2 mins make sure you understand how to solve it quickly.

If you have any time left, get a book such as the Kaplan 800 and do as many questions as possible.

Last few days, make sure you do both GMATPrep test again and again until you know everything. This will make you feel more sure about you self and lower your stress.

Finally, NEVER spend too much time in any question, guess and move on if over 3 mins.

With this strategy you should get a score in the 700s.

Good luch with your test!