A glass bulb of volume 400cm3 is connected to another of volume 200cm3 by means of a tube of negligible volume. The bulbs contain dry air and both are at a common temperature and pressure of 20∘C and 1.00 atm respectively. The larger bulb is immersed in steam at 10∘C and the smaller in melting ice at 0∘C. Find the final common pressure.