How can I solve these questions?

Q1

Question: A diver underwater sees a dolphin swimming towards him with a speed of 8.167 MS. The diver gets excited and swims towards the dolphin with a speed of 15.831 MS. The dolphin sees the diver and emits a call with a frequency of 33.09 kHz. Assume that the speed of sound through the water is 1519 m/s. Part 1) What frequency does the diver detect coming from the dolphin? f = kHZ Part 2) The sound is reected off the diver back to the dolphin. What frequency does the dolphin detect? f 2 kHz Part 3) If the dolphin and diver swim at a constant speed and are 366.8 m apart when the diver reaches 15.831 m/S, how long until they meet? 1': S Feedback for Part 1) in this case, the source (dolphin) is moving towards the observer (diver) and the observer is moving towards the source. You will need to use: f'=f