The volume is reduced to 2/3 of its original amount.
Ex: an original volume of 10L would yield a new volume of 6.67 L.
The volume of a gas is inversely proportional to its pressure and directly proportional to its temperature and the amount of gas.
Boyle showed that the volume of a sample of a gas is inversely proportional to its pressure (Boyle’s law), Charles and Gay-Lussac demonstrated that the volume of a gas is directly proportional to its temperature (in kelvins) at constant pressure (Charles’s law), and Avogadro postulated that the volume of a gas is directly proportional to the number of moles of gas present (Avogadro’s law).
Plots of the volume of gases versus temperature extrapolate to zero volume at −273.15°C, which is absolute zero (0 K), the lowest temperature possible. Charles’s law implies that the volume of a gas is directly proportional to its absolute temperature.
To learn more, see Chem.libretexts.org's Relationships among Pressure, Temperature, Volume, and Amount and Psu.edu's Gas Laws.