Two solids dissociate as follows

$\mathrm{A}\left(\mathrm{s}\right)=\mathrm{B}\left(\mathrm{g}\right)+\mathrm{C}\left(\mathrm{g}\right); {\mathrm{K}}_{{\mathrm{p}}_1}=\mathrm{x}.{\mathrm{atm}}^2$

$\mathrm{D}\left(\mathrm{s}\right)=\mathrm{C}\left(\mathrm{g}\right)+\mathrm{E}\left(\mathrm{g}\right); {\mathrm{K}}_{\mathrm{p}2}=\mathrm{y}·{\mathrm{atm}}^2$

The total pressure when both the solids dissociate simultaneously is :