The external length, breadth and height of a closed rectangular wooden box are 18cm, 10cm and 6cm respectively and thickness of wood is 1/2 cm. When the box is empty, it weight 15kg and when filled with sand it weighs 100kg. Find the weight of one cubic cm of weed and cubic cm of sand.

Explanation

To solve the problem step by step, we need to calculate the internal dimensions of the wooden box, the internal and external volumes, the weight of the wood, and finally the weight of one cubic centimeter of wood and sand.

### Step 1: Calculate the internal dimensions of the wooden box
- **External Length (L)** = 18 cm
- **External Breadth (B)** = 10 cm
- **External Height (H)** = 6 cm
- **Thickness of wood (t)** = 1/2 cm = 0.5 cm

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