A cowboy stands on horizontal ground between two parallel vertical cliffs. He is not midway between the cliffs. He fires a shot and hears it echoes. The second echo arrives 1.92s after the first and 1.47s before the third. Consider only the sound traveling parallel to the ground and reflecting from the cliffs. Take the speed of sound as 340 m/s. What is the distance between the cliffs? If he could hear a fourth echo, how long after the third echo does it arrive?
I was thinking that I could just try multiplying 340m/s by 1.92s, but this isn't correct. I thought it has something to do with the fact that he isn't standing in the center of the two cliffs. Since this didn't work I am now stumped how to get started.