What is the partial pressure of argon gas in a sealed vessel that has a total pressure of 1514 psi and partial pressures of 325 psi for oxygen and 649 psi for nitrogen?

In a sealed container of gases, the total pressure is equal to the sum of the partial pressures of the individual gases. The gases present in this vessel are argon, oxygen and nitrogen. Thus:
Total pressure = PP oxygen + PP nitrogen + PP argon
PP argon = 1514 - 325 - 649
PP argon = 540

The partial pressure of argon is 540 PSI

The answer to that would be magnesium