1. The problem statement, all variables and given/known data A rock moves so that its coordinates at the time t given by the relationships x=25t y=20t-5t^2 How high is the stone at its highest? 2. Relevant equations - 3. The attempt at a solution I got the distance the stone flies (horizental ground) by setting y=0, that gave x=100m If that is correct, how should I proceed?