Answer:
[tex]\dfrac{13}{30}\ mile[/tex]
Step-by-step explanation:
Achilles:
Rate = 13 mph
Time = t hours
Distance = D miles
Then
[tex]D=13\cdot t[/tex]
Turtle:
Rate = 1 mph
Time = t hours
Distance [tex]=D-\dfrac{2}{5}[/tex] miles
Then
[tex]D-\dfrac{2}{5}=1\cdot t[/tex]
Hence,
[tex]t=D-\dfrac{2}{5}[/tex]
and
[tex]D=13\cdot \left(D-\dfrac{2}{5}\right)\\ \\D=13D-\dfrac{26}{5}\\ \\13D-D=\dfrac{26}{5}\\ \\12D=\dfrac{26}{5}\\ \\D=\dfrac{26}{60}=\dfrac{13}{30}\ mile[/tex]