The driver of as car approaching a vertical wall notices that the frequency of his car's horn charges from 440 Hz to 480 Hz when it gets reflected from the wal. Find the speed of the car if that of the sound is `330 ms^-1`.

Explanation

To solve the problem, we will use the Doppler effect formula for sound. The frequency observed by the driver of the car changes as the car approaches a wall and the sound reflects back. Let's break down the solution step by step.

### Step 1: Understand the Doppler Effect
The Doppler effect describes how the frequency of a wave changes for an observer moving relative to the source of the wave. In this case, the car is the source of the sound, and the wall reflects the sound back to the car.

### Step 2: Set Up the Problem
Let:
- \( f_0 = 440 \, \text{Hz} \) (the original frequency of the horn)
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