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.