A mixture of He and O2 were used in the ‘air’ tanks of underwater divers for deep dives. For a particular dive 12 dm3 of O2 at 298 K, 1 atm. and 46 dm3 of He, at 298 K, 1 atm. were both pumped into a 5 dm3 tank. Calculate the partial pressure of each gas and the total pressure in the tank at 298 K.