what is the pressure of a mixture of helium, nitrogen, and oxygen...?

Question

What is the pressure of a mixture of helium, nitrogen, and oxygen if their partial pressures are 60 mm Hg 150 mmHg and 120 mmHg.

My teacher gave us this equation:
Ptotal=P1+P2+p3

600+150+102+150=1002

so then would you divide 1002 by four to get the partial pressure of al the gases?

Answer 1

Not sure where the 600 came from, but it sounds like the question wants the total pressure of all the gases combined. So you would just add together all the partial pressures, and the total pressure is 330 mm Hg.

Dividing the total pressure by the number of gases would give you the average partial pressure, but I don't think that's very useful.