Determine the distance from the person to the obstacle, if the sent sound signal, reflected from

Determine the distance from the person to the obstacle, if the sent sound signal, reflected from the obstacle, returned after 6 s.

The traversed path of the audio signal can be calculated using the formula:
S = V * t, where S = 2S1,2 (since the sound has passed the distance to the obstacle and returned), V is the speed of sound in air (V = 331 m / s), t is the time (t = 6 s).
2S1,2 = V * t;
S1,2 = V * t / 2 = 331 * 6/2 = 993 m ≈ 1 km.
Answer: The distance from a person to an obstacle is 1 km.