Question

within a group of n people, the number of possible handshakes,N, is given by N=1/2(n^2-n). How many handshakes are possible at a meeting if 30 people are present?

Answer 1

can't be

Answer 2

i'm lost

Answer 3

somewhere along the lines of, 420,870,465,435

Answer 4

N = (30^2-30)/2 = (900 - 30)/2 = 870/2 = 435 Handshakes

Answer 5

thank you sir!

Answer 6

Sorry, read it wrong at first

Answer 7

no problem

Answer 8

I prefer to write it as \[_{30}C_{2} \text{ or }{30\choose 2}\]

Answer 9

Yeah...but

Answer 10

my calculator has a built in function

ncr(30,2)=435

quick and easy

Answer 11

Isn't that nice?

Answer 12

I don't know where you got the 2 though

Answer 13

there are 30 people...pick 2 at a time to shake hands where order does not matter.