You could maybe use money?
\dfrac{3}{7} \text { of an hour = } \dfrac{1}{6} \text { of the journey}
To find 1 hour, divide both side of the equation by 3/7:
\text {1 hour = } \dfrac{1}{6} \div \dfrac{3}{7} \text { of the journey}
\text {1 hour = } \dfrac{1}{6} \times \dfrac{7}{3} \text { of the journey}
\text {1 hour = } \dfrac{7}{18} \text { of the journey}