<h2>
The impact is occurred at a distance 348.55 m far from person.</h2>
Explanation:
Let s be the distance to the impact position and t be the time when he hears the sound though concrete after impact.
Time when he hears impact through air = t + 0.90
The distance traveled by sound wave in both concrete and air is s.
Speed of sound in air = 343 m/s
Speed of sound in concrete = 3000 m/s
Distance traveled in air = Distance traveled in concrete
343 x Time when he hears impact through air = 3000 x Time when he hears impact through concrete
343 x (t + 0.90) = 3000 x t
3000t - 343 t = 343 x 0.90
2657t = 308.7
t = 0.116 s
Distance traveled in concrete = 3000 x t = 3000 x 0.116 = 348.55m
So the impact is occurred at a distance 348.55 m far from person.
