SOLUTION: Nine people exchanged presents with each other. How many presents were here?

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Question 1132538: Nine people exchanged presents with each other. How many presents were here?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

One person would give one present to the 8 others (assuming each person brought 8 presents, would not give one to themselves). If all 9 do the same, then the answer would be 8+%2A9+=+72.