W}}{{\rho }_{W}})V={{H}_{Hg}}{{\rho }_{Hg}}\times 3V\] Þ \[{{H}_{Hg}}{{\rho }_{Hg}}+{{H}_{W}}\FRAC{{{\rho }_{Hg}}}{10}=3{{H}_{Hg}}{{\rho }_{Hg}}\] Þ\[{{H}_{W}}=2{{H}_{Hg}}\times 10\]\[=\frac{2\times 75\times 10}{100}=15M\]