An engine blowing a whistle of frequency 133 Hz moves with a velocity of `60(m)/(s)` towards a hill 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 can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Values:**
- Frequency of the whistle, \( \mu = 133 \, \text{Hz} \)
- Velocity of the engine (source), \( V_s = 60 \, \text{m/s} \)
- Velocity of sound in air, \( C = 340 \, \text{m/s} \)
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