Hi, I need to solve this problem but I have no idea where to start. I made a little drawing with all the informations I have but now I'm stuck. Here's the problem: A submarine uses sonar waves, to identify other ships, by directing a highly directional acoustic pulse at a target, and computing the time duration between the transmission of the "ping", and the return of the echo. If a sub is a depth of 500m and receives a ping return in 5.6s, determine the direct distance to the ship. I'm not looking for the answer, just a little hint of what to start with. Thanks alot ! - alex.