Question

The speed of sound in water is 1500 m/s. How far away from an under-sea rock should a deep sea diver be, so that he can hear his own echo? The diver hears echo in 3 sec.

Answer 1

v = 1500 m/s.
t = 3
d = ?

2 d = v x t
2 d = 1500 x 3
 d = 1500 x 3 / 2
 d =  4500 / 2
 d = 2250 m