Solve the all parts of following question:
Question: A car is approaching a reflecting wall. A stationary observer behind the car hears a sound of frequency 790 Hz from the car horn and a sound of frequency 873 Hz from the wall.
Part A: How fast is the car traveling?
.......... km/h
Part B: What is the frequency of the car horn?
........... Hz
Part C: What frequency does the car driver hear reflected from the wall?
............ Hz
You must show your work in an efficient manner so I can understand it in clearly.