As stated previously, there are a variety of strategies used to solve this one. I've seen it 'acted' out with 35 people lining up and the first person walking along the line shaking each person's hand and then standing away from the line, the next person does the same until the last person. I've also seen a pattern being worked out, if 2 people equals 1 handshake and 3 people equals 3 handshakes, and 4 people equals 6 handshakes........and eventually the pattern is discovered. However, the algorithm to solve the question of 35 people is:
The number of hand shakes, squared, minus the number of people, divided by 2.
n2-n/2.
There would be 595 handshakes if everyone in the room shook hands with everyone once.
