<p> 0.325=Kρ<sub>x</sub><br> 0.670=K{(ρx×50+50×0.300)/(50+0.300)}<br> 解出方程得<br> ρ<sub>x</sub>=0.279mg/L<br> 或<br> ρ<sub>x</sub>=A<sub>x</sub>/(A-A<sub>x</sub>)×ρ<sub>s</sub><br> =0.325/(0.670-0.325)×(50.0×0.3)/50.3=0.281mg/L</p>