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2008 AMC 10B Question 21

AMC10 · 2008 AMC 10B

Question 21

Ten chairs are evenly spaced around a round table and numbered clockwise from $1$ through $10.$ Five married couples are to sit in the chairs with men and women alternating, and no one is to sit either next to or directly across from his or her spouse. How many seating arrangements are possible?
  1. $240$
  2. $360$
  3. $480$
  4. $540$
  5. $720$