A block and tackle system of pulleys has velocity ratio 4.
What will be its V. R. if the weight of the movable block is doubled ?

Explanation

To solve the problem, we need to understand the concept of velocity ratio (VR) in a block and tackle system of pulleys.

### Step-by-Step Solution:

1. **Understanding Velocity Ratio (VR)**:
- The velocity ratio of a pulley system is defined as the ratio of the distance moved by the effort to the distance moved by the load. It is also equal to the number of supporting strands of rope that support the movable block.

2. **Given Information**:
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