Combinatorics: when to use the Anagram grid?

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Combinatorics: when to use the Anagram grid?

by maus » Sun May 15, 2011 2:35 pm
Hi Guys,

I am really bad at combinatorics! I know how to use the anagram grid, but I ALWAYS use it in the wrong questions. Is there a way to know when you should (or shouldn't) use the grid? From what I know, the anagram grid is good when you are choosing from a group is there anything else I should know?
Maus
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by DominateTheGMAT » Sun May 15, 2011 6:13 pm
Hi Maus,

In general, the Anagram method is best used when you are choosing SOME, but not ALL members of a group. For example, if you have 8 kids in a race at recess, how many ways can they finish first, second, and third? We're not asked find how many ways all the kids can finish the race, rather just three of them.

You can still use the Anagram grid if you are choosing from all members of a group, but it's unnecessary; you should instead simply use a straight factorial. (For example, the number of ways 8 students can finish a race is simply 8!).

Honestly, I don't emphasize the anagram method with my students because there are easier and quicker ways to solve most combinatorics problems on the GMAT without resorting to complex formulas and/or the anagram method. I have a great video lesson about GMAT combinatorics at https://www.dominatethegmat.com/video-pu ... te-topics/.

I think it'll make your life a lot easier.
Brett Ethridge
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www.dominatethegmat.com