Two containers of equal volumes contain gas at pressure P1 and P2 and absolute temperature T1 and T2 respectively. On joining the vessels, the gas reaches a common pressure P and a common temperature T. The ratio is

 Two containers of equal volumes contain gas at pressure P1 and P2 and absolute temperature T1 and T2 respectively. On joining the vessels, the gas reaches a common pressure P and a common temperature T. The ratio  is