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In how many ways can 9 friends sit at a dinner table if two of them, Anna and Bob, insist on having exactly two people seated between them? (As usual, two seatings are considered the same if one is a rotation of the other.)

Mr.Owl  Oct 29, 2017
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Anchor Bob and Anna in any of two chairs......and they can be arranged in 2 ways.... [ Bob on Anna's left or right....]

 

And the other people can be arranged in 7!  = 5040 ways

 

So....the total arrangements are  2 * 7!  =   10080  ways

 

 

cool cool cool

CPhill  Oct 29, 2017

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