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Old 08-20-2013   #2
Dark88Dragon
 
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Join Date: Aug 2013
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Quote:
Originally Posted by Damitz III View Post
if twenty people are to greet each other by shaking hands. How many hand shakes are there?
Its the sum of (19+18+17+16+15...+1) because in every round 1 person shakes the hands of all the other persons, this persons hand is not needed to be shaked again. Yeah this greeting is gonna take a while, hopefully everybody washed his hands before
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