Relative Lowering Vapor Pressure

A substance ‘X’ (1.5 g) dissolved in 150 g of a solvent ‘Y’ (molar mass = 300 g mol^–1) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent ‘Y’ is _________ × 10^–2. (Nearest integer)
[Given : K_b of the solvent = 5.0 K kg mol^–1]
Assume the solution to be dilute and no association or dissociation of X takes place in solution.