Solve the given parts of following problem given below:
Problem: Dolphins of the open ocean are classified as Type II Odontocetes (toothed whales). These animals use ultrasonic clicks with a frequency of about 55 kHz to navigate and find prey.
Part A: Suppose a dolphin sends out a series of clicks that are reflected back from the bottom of the ocean 75 m below. How much time elapses before the dolphin hears the echoes of the clicks? (The speed of sound in seawater is approximately 1530 m/s.)
Part B: What is the wavelength of 55-kHz sound in the ocean?
I need help to find how much time elapses before the dolphin hears the echoes of the clicks.