The new volume wil be 3 L.
Because only the number of moles of gas is kept constant, you're going to have to use the combined gas law to solve for the new volume of the gas sample.
Rearrange the above equation to isolate
Make sure that you use the same units for pressure and that you convert the temperature from degrees Celsius to Kelvin
Rounded to one sig fig, the number of sig figs given for