A boat at anchor is rocked by waves whose troughs are 80 m apart and whose velocity is 20 m/s. How often do the crest reach the boat ?

Explanation

To solve the problem step by step, we will use the information provided about the waves and apply the relevant physics formulas.

### Step 1: Identify the Wavelength
The problem states that the troughs of the waves are 80 m apart. The wavelength (λ) is defined as the distance between two consecutive crests or troughs. Therefore, we can conclude:
- **Wavelength (λ) = 80 m**

### Step 2: Identify the Wave Velocity
The problem also provides the velocity (v) of the waves:
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