We know that
• The time of the echo to return is 1.5 seconds.
,• The speed of the sound is 340 m/s.
It's important to consider that the sound wave has a constant speed, that is, it doesn't change its velocity. Therefore, we have to use the relation
[tex]d=v\cdot t[/tex]Where t = 1.5 sec and v = 340 m/s. Let's find d
[tex]\begin{gathered} d=340m/s\cdot1.5\sec \\ d=510m \end{gathered}[/tex]