${{m}_{1}}={{m}_{2}}\Rightarrow {{\rho }_{1}}{{v}_{1}}={{\rho }_{2}}{{v}_{2}}\Rightarrow {{\rho }_{1}}{{h}_{1}}={{\rho }_{2}}{{h}_{2}}\Rightarrow {{\rho }_{1}}{{h}_{1}}=1/5{{\rho }_{1}}{{h}_{2}}\Rightarrow {{h}_{1}}=\frac{3}{2}{{h}_{2}}$ $p={{\rho }_{1}}g(\frac{3}{2}{{h}_{2}})+1/5{{\rho }_{1}}g({{h}_{1}})=3{{\rho }_{1}}g{{h}_{2}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(1)$ در حالت دوم ${{h}_{1}}'={{h}_{2}}$ است، لذا داریم: $p'={{\rho }_{1}}g{{h}_{2}}+1/5{{\rho }_{1}}g{{h}_{2}}=2/5{{\rho }_{1}}g{{h}_{2}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2)$ $(1),(2)\Rightarrow \frac{p'}{p}=\frac{2/5{{\rho }_{1}}g{{h}_{2}}}{3{{\rho }_{1}}g{{h}_{2}}}=\frac{5}{6}$