Question

There are 7 people at a party and they shake each other's hand once. How many hand shakes are there?

Answer 1

A person can only shake the hand of 6 others.....

Answer 2

i don't think that is right

Answer 3

Thank you

Answer 4

for...

Answer 5

you know for what!

Answer 6

C(2,7)=21

Answer 7

thats correct @mukushla
but where does the 2 come from?

Answer 8

is it because person A shakes hands with person B
And then person B shakes hands with person A

Answer 9

One can shake 6 so there are 7 by 6 but this counts a single handshake twice.

Answer 10

^they can't shake hands twice

Answer 11

oh i see so why is it 7C2?

Answer 12

like i get how you say its like 6+5+4+3+2+1 =21 which is the same ans as 7C2

Answer 13

@higgs the answer is 21 according to my solution book

Answer 14

Forget the handshakes, how many ways to choose 2 from 7 without regard to order?

Answer 15

why choose 2 from 7

Answer 16

2 people (ie 2 hands)

Answer 17

ohhhh i see , wow i guess thats a nice way to think about it