Question

2.
A boy standing at a distance of 172.5 m from the base of a tower
'hello'. After what time the boy can hear the echo, if the speed of
345 m/s.
1. 0.5 s.
2. 1 s.
3. 1.5s
4. 2s
​

Answer 1

here is the answer: 1. 0.5s