Answer
$\sqrt[30]{y^{27}}$
Work Step by Step
Using $a^{m/n}=\sqrt[n]{a^m}$ and the laws of exponents, then,
\begin{array}{l}
\sqrt[6]{y}\cdot\sqrt[3]{y}\cdot\sqrt[5]{y^2}
\\\\=
y^{1/6}\cdot y^{1/3}\cdot y^{2/5}
\\\\=
y^{\frac{1}{6}+\frac{1}{3}+\frac{2}{5}}
\\\\=
y^{\frac{5}{30}+\frac{10}{30}+\frac{12}{30}}
\\\\=
y^{\frac{27}{30}}
\\\\=
\sqrt[30]{y^{27}}
.\end{array}
