Suppose there are x cocks,

According to the question, the hen is three times as big as the rooster.

So hens are three times as many,

According to the question, there are more hens than cocks 18.

Provide in the form of columns:

3X-X= 18

Solution: X=9

Then 3X=27.

So there are 9 cocks and 27 hens.

Extended data:

This kind of problem belongs to the classical differential multiple problem in mathematics.

Formulas for differential multiple problems;

Difference ÷ (multiple-1) = decimal;

Decimal+difference

Or decimal × multiple = large number.

You can also use a linear equation to solve the problem.

There are five steps to solve a linear equation with one variable, namely, denominating, removing brackets, shifting terms, merging similar terms, and the transformation coefficient is 1. All steps are carried out according to the properties of algebraic expressions and equations.

To solve this equation

For example:

If you remove the denominator, you will get:

Without parentheses, you get:

To move an item, you must:

Merge similar items, get: (usually abbreviated as "merge, get:")

The coefficient becomes 1, and we get: