Answer: Boyle's law
Explanation: It states that pressure of a gas is inversely proportional to the volume of a gas at constant temperature.
[tex]P[/tex]∝[tex]\frac{1}{V}[/tex] at constant temperature
or If the pressure of gas is decreased, the volume increases if the temperature is unchanged and If the pressure of gas is increased, the volume decreases if the temperature is unchanged.
[tex]P_1V_1=P_2V_2[/tex]