Circular seating with a fixed seat for the host: A host and 8 guests are seated around a round table, but the host must occupy one specific seat. In how many ways can everyone be seated?

Difficulty: Easy

Correct Answer: 8!

Explanation:


Introduction / Context:
In circular permutations, fixing one position removes rotational symmetry. If the host is fixed at a particular labeled seat, the remaining 8 guests can be arranged freely around the table as in a line relative to that fixed reference seat.


Given Data / Assumptions:

  • One host assigned to a specific seat.
  • 8 other distinct guests to arrange.
  • Seats are effectively labeled due to the fixed reference.


Concept / Approach:

  • With host fixed, count permutations of the 8 remaining guests around the table.


Step-by-Step Solution:

Arrangements = 8! (no further symmetry remains)


Verification / Alternative check:
If instead the circle were unlabelled with no fixed person, arrangements would be (9−1)! = 8!. Here, explicitly fixing the host to a particular seat leads to the same count for the remaining guests, confirming 8!.


Why Other Options Are Wrong:

  • 9! would overcount by ignoring circular equivalence.
  • 6! or 4! are unrelated to 8 free placements.


Common Pitfalls:

  • Confusing “host fixed seat” with “host fixed position up to rotation.” Both give 8! for the others.


Final Answer:
8!

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