A pulley system has a velocity ratio of 4 and an efficiency of 90%, calculate:
The mechanical advantage of the system.

Explanation

To solve the problem, we need to calculate the mechanical advantage (MA) of a pulley system given its velocity ratio (VR) and efficiency (η).

### Step-by-Step Solution:

1. **Identify the Given Values**:
- Velocity Ratio (VR) = 4
- Efficiency (η) = 90% = 0.9 (as a decimal)

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