A car is approaching a reflecting wall. A stationary observer behind the car hears a sound of frequency 760 Hz from the car horn and a sound of...

A car is approaching a reflecting wall. A stationary observer behind the car hears a sound of frequency 760 Hz from the car horn and a sound of frequency 913 Hz from the wall.(a) How fast is the car traveling?(b) What is the frequency of the car horn?(c) What frequency does the car driver hear reflected from the wall?