see it is a simple sum.....
use first
p1v=rt here n=1 for poth cases we know t and also
for part 2
p2v=rt since rt and v is p1=p2
according to daltons law of pressure p=p1+p2 we know p1 and p2 and from this we get the volume of the container
solving it we get c=1800/1 atm
now we get v
for n2
1mole n2=0.7mole n2 +0.3 mole n
for o2
1mole 02=0.5moleo2 +0.5mole0
now again use
pv=nrt so we can know it
by again using datons law of pressure