Here is a set of free short videos for stepwise preparation of Percentage, Mixtures, and Alligations on GMAT. For a more detailed treatment of the topic, you may want to opt for our GMAT online course or our GMAT test series of 15 mock tests.
A Smart Approach to Percentage Increase and Decrease
Taking Base as 100 in Percentage Questions
Mixtures - Two Elements
Mixtures - Three or More Elements
Alligation - When and How to Use
Application of Alligation on a Question
Two high difficulty mixtures and alligation questions