The topic is not finished.COMBINATORICScreated by: walkeredited by: bb,
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This post is a part of [
GMAT MATH BOOK]
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Circular arrangementsLet's say we have 6 distinct objects, how many relatively different arrangements do we have if those objects should be placed in a circle.
The difference between placement in a row and that in a circle is following: if we shift all object by one position, we will get different arrangement in a row but the same relative arrangement in a circle.
So, for the number of circular arrangements of n objects we have:
R = \frac{n!}{n} = (n-1)!Tips and TricksAny problem in Combinatorics is a counting problem. Therefore, a key to solution is a way how to count the number of arrangements. It sounds obvious but a lot of people begin approaching to a problem with thoughts like "Should I apply C- or P- formula here?". Don't fall in this trap: define how you are going to count arrangements first, realize that your way is right and you don't miss something important, and only then use C- or P- formula if you need them.
ResourcesWalker's post with Combinatorics/probability problems: [
Combinatorics/probability Problems]
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