A sound source is moving at 85 m/s toward a stationary listener that is standing in still air. In the reference frame of the source, the listener and the air are moving toward the source at 85 m/s and the source is at rest. Suppose that the source emits sound at a frequency of 210 Hz. Suppose also that the sound travels through still air at 344 m/s. (a) At what speed, relative to the source, is the sound traveling in the region among the source and the listener? (b) Discover the wavelength of the sound in the region between the listener and the source. (c) Find the frequency heard with the listener.