Four sisters and their four husbands have been invited to a reception where these 8
Chapter 8, Problem 18(choose chapter or problem)
Four sisters and their four husbands have been invited to a reception where these 8 people are seated at 8 chairs in a row. In how many ways can they be seated if each married couple must sit next to each other and either (1) no sister sets next to any other sister or (2) each sister must set next to one of her sisters?
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