At a party, everyone shook hands with everybody else. There were 66 handshakes. How many people were at the party?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Number of handshakes will be equal to nC2 were n is the number of people ... So if
nC2=66,
We can solve for n which comes out to be 12