An ultrasound is used to measure the distance from the ship to the sea bed. A cathode ray oscilloscope (c.r.o.) placed in the ship traces a pulse sent from the ship and reflected pulse that returns. The time-base setting for the x-axis is 50 ms per division. The speed of ultrasound in water is 1500 m `s^(-1)`. Find the distance from the ship to the sea bed.
