I have been going nuts trying to get a grasp on basics. In particular, I am struggling with some of the wordy problems like distance and mixture. I find these two websites to be quite helpful. I thought I would share, it helped me a bit in understanding or at least visualize some of these problems.

https://www.onlinemathlearning.com/algeb ... blems.html

https://www.purplemath.com/modules/index.htm (Read the mixture problems, I still have to grasp the idea, but I think this pretty much cover every type of problem that I think one can encounter on GMAT. Statistically, I think there is a good chance that you will get atleast one or two questions on these two, so it may be worth a shot.