The vapour pressures of pure liquids `A` and `B` are `400` and `600 mmHg`, respectively at `298K`. On mixing the two liquids, the sum of their initial volumes is equal to the volume of the final mixture. The mole fraction of liquid `B` is `0.5` in the mixture. The vapour pressure of the final solution, the mole fractions of components `A` and `B` in vapour phase, respectively are:
