Chapter 10, Problem 83RQ

A 1.00 L container was filled by pumping into it 1.00 L of ${\text{N}}_{\text{2}}$ at 20.0 cm Hg, 1.00 L of ${\text{O}}_{\text{2}}$ at 155 torr, and 1.00 L of He at 0.450 atm. All volumes and pressures were measured at the same temperature. What was the total pressure inside the container after the mixture was made?