When equal volumes of $0.2\mathrm{M}{\mathrm{AgNO}}_3$ and $1\mathrm{MKCN}$ olutions were mixed then at equilibrium, concentration of ${\mathrm{Ag}}^{+}$ was found to be ${10}^{-6 }$M. While when equal volumes of $0.2 \mathrm{M} \mathrm{Zn}(\mathrm{NO}3 ) 2$solution and of $1 \mathrm{M} \mathrm{KCN}$ solution were mixed then at equilibrium, concentration of ${\mathrm{Zn}}^{2+}$ ion was found to be ${10}^{- 12}$ M. Then find the equilibrium constant of following 

$\begin{array}{l}2{\left[\mathrm{Ag}(\mathrm{CN}{)}_2\right]}^{-}\left(aq\right)+{\mathrm{Zn}}^{2+}\left(aq\right)\rightleftharpoons {\left[\mathrm{Zn}(\mathrm{CN}{)}_4\right]}^{2-}\left(aq\right)+2{\mathrm{Ag}}^{+}\left(aq\right)\end{array}$