I recommend doing the QR problems in DAT destroyer for understanding, meaning don't time yourself and learn how to do them all. Then, with Math destroyer time yourself and simulate it as part of the test. I was getting about 30-32 right in practice test 1-5 in 45 minutes and that made the test seem easy. Granted, there were a couple problems I didn't know how to do but I finished 10 minutes early because MD is so much harder. It wouldn't have mattered if I had 3 hrs for QR, there were a couple I would not have gotten but that's ok...you're just trying to do well enough on QR that it doesn't hinder your AA significantly.