Two fathers and two sons go on a fishing trip. However, there are only three people on the trip. How is this possible?

Grandfather, father, son.
The grandfather is a father.
The son is a son.
But the father is both a son and a father.
:)

becauze 2+2=3

wtf?

It's a grandfather, a father, and a son.

there's a grandfather, a father, and a son.

The 2 boys are brothers or what Chann94 said.

A grandfather, father and a son.

There are two fathers, but there is a grandfather, a father, and a son. The grandfather is a father to the father, and the father is a father to the son.