Video: OG Diag Explanation: DS #39

August 6, 2010

Today's video covers another Data Sufficiency question from the diagnostic test of the Official Guide.

This one is a tricky coordinate geometry example. It demands an intuitive understanding of slope. Calculating slope is one thing, but handling different slopes and their ramifications is much more demanding.

In the video, I explain how to attack this particular problem, and also talk about some of the key insights the GMAT requires in coordinate geometry.

Remember, I've created (print) explanations to every Quant problem in The Official Guide for GMAT Review and The Official Guide for Quantitative Review. Find out more about those resources here.

About the author: Jeff Sackmann has written many GMAT preparation books, including the popular Total GMAT Math, Total GMAT Verbal, and GMAT 111. He has also created explanations for problems in The Official Guide, as well as 1,800 practice GMAT math questions.

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