Evelyn Glennie Listens to Sound without Hearing It |Her music journey Begin

A car is moving with a speed of 72 km-hour^(-1) towards a roadside source that enits sound at a frequency of 850 Hz. The car driver listens to the sound while approching the source and again while moving away from the source after crossing it. If the velocity of sound is 340 ms^(-1) , the difference of the two frequencies the driver hears is

A car is moving with a speed of 72 "km-hour"^(-1) towards a roadside source that emits sound at a frequency of 850 Hz. The car driver listens to the sound while approaching the source and again while moving away from the source after crossing it. If the velocity of sound is 340 ms^(-1) , the difference of the two frequencies, the driver hears is