A boy receives the echo of his clap reflected by a nearby hill 0.8s later. How far is he from the hill?

A. 528m
B. 66m
C. 136m
D. 264m

Correct Answer:

Option C – 136m

Explanation

Time for echo both ways = 0.8
Therefore time for echo in 1 way = 0.8/2 = 0.4

Distance = Speed x time

Distance = 340 x 0.4

Distance = 136m