The new volume : 0.07 L
Boyle's Law
At a constant temperature, the gas volume is inversely proportional to the pressure applied
[tex]\rm p_1V_1=p_2.V_2\\\\\dfrac{p_1}{p_2}=\dfrac{V_2}{V_1}[/tex]
P₁=1 atm
V₁=0.39 L
P₂=5.6 atm
[tex]\tt V_2=\dfrac{P_1.V_1}{P_2}\\\\V_2=\dfrac{1\times 0.39}{5.6}\\\\v_2=\boxed{\bold{0.07~L}}[/tex]