Liquid Solution

Calculate the number of moles of nonvolatile solute dissolved in 0.3 kg solvent if $\Delta \mathrm{T}_{\mathrm{b}}=0.3 \mathrm{~K}$ and $\mathrm{K}_{\mathrm{b}}$ for solvent is $1.8 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$.