By ideal gas equation we can say
PV = nRT
P = pressure
V = volume
n = number of moles
R = avagadro gas constant
T = temperature
So from above expression we can see that for constant number of moles we can say
[tex]\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}[/tex]
[tex]\frac{101*12}{273+22} = \frac{20*V_2}{273-30}[/tex]
[tex]4.11 = 0.082*V_2[/tex]
[tex] V_2 = 50 m^3[/tex]
So finally the volume will be 50 m^3