Write the repeating decimal $0.\overline{515}$ as a fully simplified fraction.
+486 Let $x=0.\overline{515}$.
Multiplying both sides by 1000 gives: $1000x=515.\overline{515}$
Subtract x from 1000x to get rid of the repeating part: $1000x-x=515$ so $999x=515$
Dividing both sides by 999 gives $\boxed{x=0.\overline{515}=515/999}$
