Permutation: Circular
How to solve a circular permutation: formula, 1 example, and its solution.
Formula
The number of ways
to arrange n things in a circle is
(n - 1)!.
This is the circular permutation formula.
Example5 Students, Round Table
Solution
Solution (Detail)
There are 5 students.
They are sitting at a round table.
This is arranging 5 students
in a circle.
So the number of the ways is,
5 - 1,
4!.
4! = 4⋅3⋅2⋅1
Factorial
4⋅3 = 12
2⋅1 = 2
12⋅2 = 24
So the answer is 24.