two elements a and b form compounds having

Question

Two elements A and B form compounds having molecular formulae AB² and AB⁴. dissolved in 2O g of benzene, 1 g of AB2 lower the freezing point by 2.3 K, whereas 1 g of AB4 lowers it by 1.3 K. The molar depression constant for benzene is 5.1 K kg mol^-1. Calculate the atomic masses of A and B