Pure water has vapour pressure $23.8\mathrm{mmHg}$ at $298\mathrm{K}$. A solution is prepared by dissolving $3.0\mathrm{g}$ of urea (molar mass $60$) and $3.6\mathrm{g}$ of glucose (molar mass $180$), both non-volatile non-electrolytes, in $90\mathrm{g}$ of water (molar mass $18$). Calculate the lowering of vapour pressure in mmHg to two decimal places.

Numerical answer type, answer in mmHg, tolerance 0.005.