An engine blowing a whistle of frequency 133 Hz moves with a velocity of `60(m)/(s)` towards a hiss from which an echo is heard. Calculate the frequency of the echo heard by the driver. (velocity of sound in air in `340(m)/(s)`.)

Explanation

To solve the problem of calculating the frequency of the echo heard by the driver of the engine blowing a whistle, we will use the Doppler Effect principles. Here’s a step-by-step solution:

### Step 1: Understand the Problem
The engine is moving towards a wall while emitting a sound at a frequency of 133 Hz. The sound reflects off the wall (echo) and the driver hears this reflected sound. We need to calculate the frequency of the echo heard by the driver.

### Step 2: Identify the Given Values
- Frequency of the whistle (source frequency, \( f_s \)): 133 Hz
- Velocity of the engine (source velocity, \( V_s \)): 60 m/s
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