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Can you help me solve this difficult problem?

60 people want to ride a rollercoaster as many times as possible. The rollercoaster has 30 cars that each have 2 seats. They may ride as many times as they want as long as everybody rides each time and nobody can sit with the same person more than once. What is the greatest possible number of times they can ride? And why?

Update:

It cannot be 59 because if everybody moves clockwise, they will just end up sitting with the same 2 people 30 times each. This would work to get to 30 by just having 30 shift 1 spot while the other stay still, but this would not be the maximum.

1 Answer

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  • Anonymous
    1 decade ago
    Favorite Answer

    Since there are 59 other people a person could possibly sit next to, and it has to be different each time, then that means there can't be more than 59 rides.

    Think of having all 60 people sitting in place, then after each ride everybody gets up and moves clockwise to the next seat. This is one way to do it and get exactly 59 rides.

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