\[4\sqrt{\frac{3}{8}} = \sqrt{16 \cdot \frac{3}{8}} = \sqrt{6};\]
\[\frac{1}{5}\sqrt{150} = \sqrt{\frac{1}{25} \cdot 150} = \sqrt{6};\]
\[4\sqrt{\frac{3}{8}} = \frac{1}{5}\sqrt{150}.\]