Answer:
309 m
Explanation:
time apart = 0.8 s
speed of sound in air = 343 m/s
speed of sound in concrete = 3000 m/s
lets assume it time it takes to travel trough concrete = T
the time it takes to travel through air = T + 0.8 since they are 0.8 s apart
the distance traveled by both waves is the same, so we can equate the distance for both waves
distance = speed x time
- for concrete, distance = 3000 x T
- for air, distance = 343 x (T + 0.8)
now equating the two distance together we have
3000 x T = 343 x (T + 0.8)
3000T = 343T + 274.4
3000T - 343T = 274.4
T = 0.103 s
recall that distance = 3000 x T = 3000 x 0.103 = 309 m
