Question

What is the total pressure in mm Hg of a gas mixture containing argon gas at 0.25 atm helium gas at 350 mm,Hg, and nitrogen gas at 360 torr.

Answer 1

Dalton's Law of Parital Pressure says that the total pressure of a system is the sum of the individual partial pressures of each gas. The only thing you need to do is to decide which unit and change the other two. I would change atm to mm and torr to mm.