JEE Advanced 2018 Chemistry question

Liquids **A** and **B** form ideal solution over the entire range of composition. At temperature T, equimolar binary solution of liquids **A** and **B** has vapour pressure 45 Torr. At the same temperature, a new solution of **A** and **B** having mole fractions and , respectively, has vapour pressure of 22.5 Torr. The value of in the new solution is . (given that the vapour pressure of pure liquid **A** is 20 Torr at temperature T)