July 16, 2015
This is not your typical section in a GMAT quantitative review; however, there is no other place to put the few topics that fall into GMAT sets. Also, much of what is learned in a few of these subjects can be used to simplify problems in other areas. Average and weighted average especially will offer some core ways to think about other problems. Just because this is the shortest section does not mean that it is not important. Like always, study diligently and it will pay off in the end.