Answer:
t = 0.029 s
Step-by-step explanation:
We have,
Speed of sound is 343 m/s.
Dezeirey is positioned 5 m behind her.
It is required to find the time taken for the echo from the wall to reach her. The total distance covered by the echo when it reaches her is 2d or 10 m.
Time taken,
![t=(d)/(v)\\\\t=(10\ m)/(343\ m/s)\\\\t=0.029\ s](https://img.qammunity.org/2021/formulas/physics/college/nzn71ai4y1jgw8h9qc8o2csm9mqwgztibs.png)
So, it will take 0.029 seconds for the echo from the wall to reach her.