Answer:
[tex]Distance=\frac{13}{30}\ miles[/tex]
Step-by-step explanation:
Let Achillies completed the distance in [tex]t\ hours[/tex].
[tex]distance(s)=speed\times time\\\\s=13\times t=13t\\\\In\ t\ hours\ distance\ covered\ by\ turtle=speed\ of\ turtle\times time=1\times t=t\\\\Turtle\ was\ \frac{2}{5}\ of\ total\ mile\ behind\ Achillies\\\\s-t=\frac{2}{5}\\\\s-\frac{s}{13}=\frac{2}{5}\ \ \ \ \ \ \ (as\ s=13t\Rightarrow t=\frac{s}{13})\\\\\frac{12}{13}s=\frac{2}{5}\\\\s=\frac{13}{30}\ miles[/tex]