Inactive Tutor answered 06/06/21
The time delay is discernible because you see the runner start and then hear the wound 0.4 seconds later.
Since the speed of sound is constant at about 330 m/s in air, we can use d = vt, there d is the distance desired, v is the speed of sound and t is the time delay.
Plugging in we get d = 330 (0.4) = 132 m.