A car approaches a truck are approaching each other from opposite directions on a two-lane road and the truck honks its horn before thee vehicles pass each other.

The car has a speed of 16 m/s, while the truckihas a speed of 27 m/s. If the temperature of the air is 20 degrees Celsius, and the driver in the car hears the truck's horn at a frequency of 969 Hz, what is the frequency of sound emittedby the truck horn.