Chiu Chang Suann Jing/Examples/Example 2

Example of Problem from

 * Suppose that there are a number of rabbits and pheasants confined in a cage,
 * in all thirty-five heads and ninety-four feet;
 * required the number of each?

Solution
There are $12$ rabbits and $23$ pheasants.

Proof
Let $r$ be the number of rabbits.

Let $p$ be the number of pheasants.

It is assumed that the rabbits all have $4$ feet and the pheasants $2$.

Then: