Answer:
[tex]10\dfrac{2}{7}\ miles[/tex]
Step-by-step explanation:
If Kevin walked his dog 1 2/7 miles and Sam walked his dog 7 times as far, then Sam walked his dog
[tex]1\dfrac{2}{7}\cdot 7=\dfrac{1\cdot 7+2}{7}\cdot 7=\dfrac{9}{7}\cdot \dfrac{7}{1}=9\ miles.[/tex]
Together they walked
[tex]1\dfrac{2}{7}+9=10\dfrac{2}{7}\ miles.[/tex]