At the start of a trip, the odometer on a car read 21,395. at the end of the trip, 13.5 hours later, the odometer read 22,125. assume the scale on the odometer is in miles. what is the average speed the car traveled during this trip?

54.81 mph

Explanation:

Initial reading on the odometer = 21395 miles

Final reading on the odometer = 22125 miles

Total time the car travelled =  13.5 hours

Distance covered by the car

22125-21395 = 740 miles

As acceleration is not given assume it as constant.

Speed = Distance / time

∴ Average speed the car traveled during this trip is 54.81 mph

The question is not well presented.

There is   shift in sound  frequency for observers towards  whom the source is approaching.

The  gap should be filled with an apparent upward

Explanation:

The Doppler effect (also referred to as the Doppler shift) is the difference in frequency of a wave when related to an observer who has a relative movement to the wave source

The Doppler effect can be observed to occur with all types of waves - most notably water waves, sound waves, and light waves

The Doppler effect describes sound as an effect which is produced from a moving source of wave.

According to the Doppler effect;

When the source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching.