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In how many ways can 15 people be seated around two round tables with seating capacities of 7 and 8 people? |
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Answer: Option C Explanation: Circular Permutation 'n' objects can be arranged around a circle in (n1)! If arranging these 'n' objects clockwise or counter clockwise means one and the same, then the number arrangements will be half that number.
You can choose the 7 people to sit in the first table in 15C7 ways. After selecting 7 people for the table that can seat 7 people, they can be seated in: (71)! = 6! The remaining 8 people can be made to sit around the second circular table in: (81)! =7! Ways. Hence, total number of ways: 15C8 × 6! × 7! |
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