According to the kinetic theory of gases and Boyle's law, pressure and the number of particles in a gas are directly proportional. This relationship can be expressed mathematically as:

$$P \propto n$$

Where:

- P represents pressure

- n represents the number of particles

This means that as the number of particles in a gas increases while volume and temperature remain constant, the pressure of the gas also increases proportionately. Conversely, as the number of particles decreases, the pressure decreases as well.

In more detail, pressure is the result of the collision of gas particles with the walls of their container. When there are more particles in a given volume, the frequency of these collisions increases, leading to a higher pressure.