3. \(\sqrt[5]{11^{10}:4^{15}}\)

\[\sqrt[5]{\frac{11^{10}}{4^{15}}}=\frac{11^{10:5}}{4^{15:5}}=\frac{11^2}{4^3}=\frac{121}{64}\]

Ответ: \(\frac{121}{64}\).