Exercise · ZW-ORBIT-STABILIZER-THEOREM-008 · ★★☆ Intermediate

A group of order \(60\) acts on \(X\) with a single orbit, and the stabilizer of each point has \(5\) elements. How many elements does \(X\) have?

Choose one option.

Show answer
  • D. \(12\)

Explanation

Since \(X\) is a single orbit, \(|X|=|G|/|\mathrm{Stab}(x)|=60/5=12\).

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Review the concept: Orbit-stabilizer theorem

For a finite group \(G\) acting on \(X\) and an element \(x\in X\), the size of the orbit of \(x\) is the index of its stabilizer in \(G\).

\[|\mathrm{Orb}(x)|=[G:\mathrm{Stab}(x)]=\frac{|G|}{|\mathrm{Stab}(x)|}\]

More practice problems: orbit-stabilizer theorem

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