How fast does the sound reach a person?

Depending on the environment in which the person is, the sound will reach his ear at such a speed.
The smallest speed in gases. More – in the liquid. The largest is in steel, aluminum, etc.
In air, the speed of sound is 331 m / s. Therefore, if a person standing 700 meters away from you shouts something, then you will hear him only after two seconds.
The simplest demonstration of the speed of sound is by putting your ear to the rail. You can hear the sound of the wheels of the train several kilometers before you, but you should not do this for safety reasons.