A ship sends out returns from the ultrasound that seabed is detected after 4 s. If the speed of ultrasound through sea water is 1550 m s^-1, find the distance of the seabed from the ship

Here, t = 4 s,
V = 1550 m s^-1,
d = ?
Now, d = V x t/ 2
= 1550 x 4 / 2 = 3100 m = 3.1 km