[tex]1~\text{h}=60~\mathrm{min}~~\Leftrightarrow~~\boxed{\begin{array}{c} 1\mathrm{~min}=\dfrac{1}{60}\mathrm{~h} \end{array}}[/tex]
Therefore,
[tex]\dfrac{2}{3}~\dfrac{\mathrm{mile}}{10\mathrm{~min}}\\ \\ \\ =\dfrac{2}{3}~\dfrac{\mathrm{mile}}{10\cdot (\frac{1}{60}~\mathrm{min})}\\ \\ \\ =\dfrac{2}{3}~\dfrac{\mathrm{mile}}{\frac{10}{60}~\mathrm{min}}\\ \\ \\ =\dfrac{2}{3}~\dfrac{\mathrm{mile}}{\frac{1}{6}~\mathrm{min}}\\ \\ \\ =\dfrac{2}{3\cdot \frac{1}{6}}~\dfrac{\mathrm{mile}}{\mathrm{min}}\\ \\ \\ =\dfrac{2}{(\frac{3}{6})}~\dfrac{\mathrm{mile}}{\mathrm{min}}\\ \\ \\ =2\cdot \dfrac{6}{3}~\dfrac{\mathrm{mile}}{\mathrm{min}}\\ \\ \\ =2\cdot 2~\dfrac{\mathrm{mile}}{\mathrm{min}}\\ \\ \\ =4~\dfrac{\mathrm{miles}}{\mathrm{min}}[/tex]
