To determine how far David traveled, we can set up the equation based on the total distance traveled by both Mark and David.
Let \( d \) represent the distance David traveled. The relationship can be described by the following equation:
\[ 255 + d = 570 \]
This equation indicates that the distance Mark traveled (255 miles) plus the distance David traveled (\( d \)) equals the total distance (570 miles).
To solve for \( d \), you would subtract 255 from both sides:
\[ d = 570 - 255 \]
Thus, the equation you can use to solve the problem is \( 255 + d = 570 \).