Can someone explain the math behind this clip?

He was just discussing several different ways to split the money. There were 4 groups of people (one per car); the first contained 2 people, the second 1 person, the third 3 people, and the fourth 2 people. At first he suggested splitting the money evenly over the 4 groups. But then the group with 3 people didn't like that and they wanted to split the money evenly over the 8 people there. This wasn't good enough for the fourth group, so then the one guy came up with a more complicated strategy. In it, there were other factors involved where each person's actions determined how many of 25 shares each group got. For having a car, each group got 1 share. Each person also gave the group 1 share each, and so on.