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Inclusion and Exclusion and the new GMAT

Dublin native Colm Mulcahy has been in the Department of Mathematics at Spelman College since 1988. His interests include algebra, number theory, geometry and mathematical card principles and effects. Follow him on Twitter at @CardColm and also check out @WWMGT

The last question, under the heading “Two-Part Analysis”, at the end of this NYT article (from July 2011) on the new GMAT seems to be deliberately worded in a way that forces one to read and think very carefully.

It takes a while to even process the question as it’s asked! I’m assuming that was intentional.

I’m curious how “they” intended people to solve this. Exclude impossible answers until only one is still Included?  I guess so.

Yes, it can also be solved quickly using the Inclusion Exclusion principle (click for a spoiler).

Thanks to my Econ colleague Jack Stone at Spelman for passing this along.

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