-10. represents 10 seconds before the runner finish his first lab 10 represents 10 seconds after the runners finish his first lab what does zero represent in this situation
If -10 is 10 seconds before he finishes his first lap, and 10 is 10 seconds after he finishes his first lap, whats in the middle of that?! 0 of course, so thats when he finishes his first lap.
