Answer
$ \displaystyle \frac{1}{x^{3}y}$
Work Step by Step
Note that:
$\displaystyle \frac{x^{-2}y}{xy^{2}}=\frac{x^{-2}}{x}\cdot\frac{y}{y^{2}}\quad$
Apply rule $\displaystyle \quad \frac{a^{m}}{a^{n}}=a^{m-n}$
$=x^{-2-1}y^{1-2}$
$=x^{-3}y^{-1}\quad$.
Apply rule $\displaystyle \quad a^{-n}=\frac{1}{a^{n}}$
$=\displaystyle \frac{1}{x^{3}}\cdot\frac{1}{y}$
$=\displaystyle \frac{1}{x^{3}y}$