Question 16
If $$
\frac{y}{x-z}=\frac{x+y}{z}=\frac{x}{y}
$$ for three positive numbers $x,$ $y,$ and $z,$ all different, then $\frac{x}{y}=$
\frac{y}{x-z}=\frac{x+y}{z}=\frac{x}{y}
$$ for three positive numbers $x,$ $y,$ and $z,$ all different, then $\frac{x}{y}=$