\(\because \,\,\frac{{P_{solvent}^0\, - \,\,{P_{solution}}}}{{{P_{solution}}}}\,\, = \,\,\frac{{{n_{solute}}}}{{{N_{solvent}}}}\)
\(\frac{{760\,\, - \,\,{P_s}}}{{{P_s}}}\,\, = \,\,\,\frac{{18\,\, \times \,\,18}}{{180\,\, \times \,\,178.2}}\)
\( \Rightarrow \,\,{P_s}\, = \,\,752.40\,\,torr\)