# Two Fathers and Two Sons Leaving Town

## Classic Problem

Two fathers and two sons leave town.

This reduces the population of the town by three.

## Solution

This is an instance of the riddle Two Fathers and Two Sons who are Three People.

The $3$ people involved are grandfather, father and son.

## Historical Note

Eugene P. Northrop opens his Riddles in Mathematics of $1944$ with this riddle.

He takes care to categorise it as a paradox.

It is another instance of the Three Pheasants riddle, which appears in a work of Niccolò Fontana Tartaglia dating from the mid-$16$th century.