A hollow cylindrical tube open at both end is made of iron 2 cm thick. If the external diameter be 50 cm and the length of the tube is 210 cm, find the number of cubic cm of iron in it.

Explanation

To find the number of cubic centimeters of iron in the hollow cylindrical tube, we will calculate the volume of the iron that makes up the tube. This can be done by finding the volume of the outer cylinder and subtracting the volume of the inner cylinder.

### Step-by-Step Solution:

1. **Identify the given values:**
- External diameter of the tube = 50 cm
- Thickness of the tube = 2 cm
- Length of the tube (height) = 210 cm
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