Step-by-step explanation: So there is 4 people and lets say I'm one of them, so I shake hands with 3 people, that's 3 handshakes, then one of those 3 people shake hands with the other 2, that's 5 handshakes, and then the last 2 shake hands with each other since they haven't, so that's 1 more which means 6 handshakes.
