Sal Khan
Sal works through problems in the 11th edition of the official GMAC GMAT Review (ISBN Number: 0-9765709-0-4 published in 2005). You should take the practice tests on your own, grade them and then use these videos to understand the problems you didn't get. Source: Khan Academy (www.khanacademy.org), used under the Creative Commons Attribution-NonCommercial-ShareAlike (CC BY-NC-SA) license. All Khan Academy content is available for free at www.khanacademy.org. Khan Academy does not endorse the World Public Library.
Read this work at the World Public Library (library card needed).