There was a small get-together. There were a total of 28 handshakes exchanged between the guests. How many guests were present?
Answer
There were 8 guests.
If there are 2 guests, there will be 1 handshake. So,
2 guests, 1 handshake
3 guests, 2 handshakes
3 guests, 3 handshakes
4 guests, 6 handshakes
With this, for n guests, we will have (n(n-1))/2 handshakes.