A gaseous mixture of helium and neon at #1*atm# contains a partial pressure of #0.60*atm# with respect to helium. What is #P_"Ne"#?
Dalton's law of partial pressures holds that in the gaseous mixture, the partial pressure exerted by a component is the same as the pressure as it would exert if it ALONE occupied the container. The total pressure is the sum of the individual partial pressures.
For a more general treatment, see here.