SOLUTION: there's a total of 78 handshakes and the equation is h=p(p-1)/2 so how many people are there in a group?
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Question 451003: there's a total of 78 handshakes and the equation is h=p(p-1)/2 so how many people are there in a group?
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
h=p(p-1)/2
set h to 78 and solve for p:
78=p(p-1)/2
156=p(p-1)
156=p^2-p
0=p^2-p-156
0=(p+12)(p-13)
p = {-12, 13}
throw out the negative solution leaving
p = 13 people
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