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