For those who want to focus more on counting (combinations and permutations) and Probability, I found a great source to read up and understand the concepts.
I got the book from my local library and have very impressed with the coverage... some of the problems are very much like the GMAT which gives me confidence that the book will be helpful.
The title: Introduction to Counting & Probability by David Patrick
Attached : For Math geeks.... an extra set of problems Smile
Couple of related links:
http://www.artofproblemsolving.com/Book ... ?page_id=3