CAT 2018 Averages — Previous Year Question

The arithmetic mean of $x, y$ and $z$ is $80$, and that of $x, y, z, u$ and $v$ is $75$, where $u = \tfrac{(x+y)}{2}$ and $v = \tfrac{(y+z)}{2}$. If $x \geq z$, then the minimum possible value of $x$ is (TITA).