A person standing on a road sends a sound signal to the driver of a car going away from him at a speed of 72 km/h. The signal travelling at 330 m/s in air and having a frequency of 1600 Hz gets reflected from the body of the car and returns. Find the frequency of the reflected signal as heard by the person.

Explanation

To solve the problem step by step, we need to calculate the frequency of the sound signal as heard by the person after it is reflected from the car. We will use the Doppler effect formula for both the outgoing and incoming signals.

### Step-by-Step Solution:

1. **Convert the speed of the car from km/h to m/s**:
\[ u = 72 \text{ km/h} = 72 \times \frac{5}{18} = 20 \text{ m/s} \]
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