Respuesta :

Answer:

d = 513 m

Explanation:

Given that,

An echo returned in 3s.

We need to find the distance of the reflecting surface from the source, given that the speed of sound is 342 m/s.

The sound will cover 2d distance. The formula for the speed is given by :

v = d/t

So,

[tex]v=\dfrac{2d}{t}\\\\d=\dfrac{vt}{2}\\\\d=\dfrac{342\times 3}{2}\\\\d=513\ m[/tex]

So, the required distance is 513 m.