Frankly GMAT ting!

This is a video I found on ScoreChase.com. Its a sample video, still it talks about Basic Counting Principle, one of the very important principles used in both Probability and Permutation, combinations questions. This is a part of their Math workshop on Probability, Permutations and Combinations which is available at quite affordable price. Having seen the real presentation, I can safely say that this presentation is of lower quality just for demonstration purposes. The real presentation is actually of much better quality.

Demo of Probability, permutations and combinations E-Workshop