Answer
$\sqrt[10]{b}$
Work Step by Step
Using $a^{m/n}=\sqrt[n]{a^m}$ and the laws of exponents, then,
\begin{array}{l}
\dfrac{\sqrt[5]{b^2}}{\sqrt[10]{b^3}}
\\\\=
\dfrac{b^{2/5}}{b^{3/10}}
\\\\=
b^{\frac{2}{5}-\frac{3}{10}}
\\\\=
b^{\frac{4}{10}-\frac{3}{10}}
\\\\=
b^{\frac{1}{10}}
\\\\=
\sqrt[10]{b}
.\end{array}
