Which one is not correct mathematical equation for Dalton's Law of...

Dalton’s law of partial pressures is a gas law which states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures exerted by each individual gas in the mixture.

$P = {P}_{1} + {P}_{2} + {P}_{3}$

${P}_{1}, {P}_{2}and{P}_{3}$ are the partial pressures and $P$ is the total pressure.

According to ideal gas equation

${P}_{1} = \dfrac{{n}_{1}RT}{V}, {P}_{2} = \dfrac{{n}_{2}RT}{V}and{P}_{3} = \dfrac{{n}_{3}RT}{V}$

Partial pressure of the individual gas can be expressed as follows,

${P}_{i} = {X}_{i}P$, $P$ is total pressure.