1 mole of helium gas
the volume of one mole of helium gas is V=22.4L (this is the so-called molar volume of any gas)
so the volume initial is V1= V+ Vcontainer =22.4L + 2L=24.4L
according to boyles Law
P1 /V1 = P2 /V2
and 1kPa = 0.009 atm
105.0 kPa= 0.94 atm
so P2 = V2 x P1 / V1= 1.5 x 0.95 / 24.4 = 0.05 atm