[tex]\displaystyle\\
\left[\left(\frac{3}{5}\right)^6\right]^{10}=\left\{\left[\frac{9}{25}\right]^5 \right\}^n\\
\left[\left(\frac{3}{5}\right)^6\right]^{10}=\left\{\left[\frac{3^2}{5^2}\right]^5 \right\}^n\\
\left[\left(\frac{3}{5}\right)^6\right]^{10}=\left\{\left[\left(\frac{3}{5}\right)^2 \right]^5 \right\}^n\\
\left(\frac{3}{5}\right)^{6\times10}=\left(\frac{3}{5}\right)^{2\times5\times n} \\
\left(\frac{3}{5}\right)^{60}=\left(\frac{3}{5}\right)^{10n}\\\\
10n=60\\
n=\frac{60}{10}\\
\boxed{\bf n=6}[/tex]