In one container, there is $80 \mathrm{~cm}^{3}$ of a salt solution with a density of $1.2 \mathrm{g} / \mathrm{cm}^{3}$, and in another container, there is $100 \mathrm{~cm}^{3}$ of an ammonia solution with a density of $0.8 \mathrm{g} / \mathrm{cm}^{3}$. From the first container, $x \mathrm{~cm}^{3}$ is poured into the second one; after thorough mixing, $x \mathrm{~cm}^{3}$ is poured back into the first one. What is $x$, if after the pouring back, the liquid in both containers has the same weight?