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In how many ways can a family of six people be seated at a round table if the youngest kid must sit next to at least one of the parents?

 Jul 9, 2021
 #1
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i'm assuming there are 2 parents... Answer should be 5! - 3!3! = 120 - 36 = 84...correct me if im wrong

 Jul 9, 2021
 #2
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Assume  that   the  child sits in seat   1

 

Count  the number of ways   that  the  child  CANNOT  sit next to  either  parent

 

They   must  sit in   seats   3, 4      3,5   or    4,5  

 

They  can sit  2 ways  in either seats 3,4 , 3,5  or  4,5   and for each of these, the  other people (not counting the  child) can be arranged in  3! ways  =       3 (2)(3!)   =  36  ways

 

Total arrangements  =  5!  =  120

 

So.....the  ways  the child CAN sit next to at lrast one of the parets =  120  - 36  =   84

 

{ The Guest  and I agree  !!!  }

 

cool cool cool

 Jul 9, 2021

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