Answer
$\color{blue}{\frac{1}{s}\sqrt[6]{r}}$
Work Step by Step
Factor the radicand so that one factor is a perfect sixth power to obtain:
$=\sqrt[6]{\left(\frac{1}{s^6}\right)(r)}
\\=\sqrt[6]{\left(\frac{1}{s}\right)^6(r)}$
Bring out the cube root of the perfect cube factor to obtain:
$\\=\color{blue}{\frac{1}{s}\sqrt[6]{r}}$