Here's why:

* Boyle's Law states that the volume of a gas is inversely proportional to its pressure, when the temperature and the amount of gas (number of moles, n) are held constant.

Mathematically, it's represented as:

P₁V₁ = P₂V₂

where:

* P₁ and V₁ are the initial pressure and volume

* P₂ and V₂ are the final pressure and volume

Let me know if you'd like more information on gas laws!