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