When the pressure exerted on a confined gas at constant temperature is doubled, the volume of the gas is halved.

This is directly related to Boyle's Law, which states:

* For a fixed amount of an ideal gas kept at a constant temperature, pressure and volume are inversely proportional.

Mathematically, this is represented as:

* P₁V₁ = P₂V₂

Where:

* P₁ = Initial pressure

* V₁ = Initial volume

* P₂ = Final pressure

* V₂ = Final volume

If you double the pressure (P₂ = 2P₁), then the volume must be halved (V₂ = V₁/2) to keep the equation balanced.