Difficulty: Medium
Correct Answer: 12
Explanation:
Introduction / Context:
Counting circular bead arrangements where reflections (flips) are considered identical uses necklace or “free” circular permutations. For n distinct beads on a loop with flips identical, the count is (n − 1)! / 2 for n ≥ 3 (when no additional symmetries collide distinct colorings in general position).
Given Data / Assumptions:
Concept / Approach:
Step-by-Step Solution:
Verification / Alternative check:
Polya’s enumeration for all-distinct colors also yields (n−1)!/2 when flips are identified, matching 12 for n=5.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
12
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