The boy standing by the cliff heard the echo of his voice after 2s. What is the distance from the boy to the rock?

Given:
V = 340 m / s.
t = 2 s.
Solution:
The traversed path of the echo sound can be calculated using the formula:
2S = V * t, where 2S is the path traversed by the sound (the sound reached the rock, reflected from it and came back), V is the speed of sound propagation in the air (V = 340 m / s), t is the time it takes for the echo sound to be heard ( t = 2 s).
Let’s calculate the distance from the boy to the rock:
S = V * t / 2 = 340 * 2/2 = 340 m.
Answer: The distance from the boy to the rock is 340 m.