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A car P travelling at 20 ms –1 sounds its horn at a frequency of 400 Hz. Another car Q is travelling behind the first car in the same direction with a velocity 40 ms –1 . The frequency heard by the passenger of the car Q is approximately [Take, velocity of sound = 360 ms –1 ]

1. 421 Hz
2. 471 Hz
3. 485 Hz
4. 514 Hz

Correct answer: 471 Hz

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