By Vince Kotchian. Full-time GRE tutor since 2007, author of Barron's 6 GRE Practice Tests, three perfect 170 verbal scores on the real GRE, and moderator of r/GRE.
The main complaint I hear regarding combinatorics - that is, permutation and combination questions - is "what the hell am I looking at? Which one is it?" It can be hard to decipher whether the question involves a permutation - in which order matters - or a combination - in which order does NOT matter.
In this brief video, I cover some tips about how to tell the difference between permutations and combinations as they appear on GRE quantitative sections.
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