A mixture contains 18% copper by weight. How much mixture an kg.) is required to obtain 1 kg.of copper?

Options

A. 350
B. 300
C. 450
D. 250

Answer

To solve the problem of how much mixture is required to obtain 1 kg of copper when the mixture contains 18% copper by weight, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Percentage**: The mixture contains 18% copper. This means that in every 100 grams of the mixture, there are 18 grams of copper.

2. **Calculate the Amount of Mixture for 1 Gram of Copper**:
- If 100 grams of the mixture contains 18 grams of copper, then for 1 gram of copper, the amount of mixture required can be calculated as:
\[ \text{Mixture for 1 gram of copper} = \frac{100 \text{ grams}}{18 \text{ grams}} \approx 5.56 \text{ grams} \]

3. **Calculate the Amount of Mixture for 1 kg of Copper**:
- Since 1 kg is equal to 1000 grams, we need to find out how much mixture is required for 1000 grams of copper:
\[ \text{Mixture for 1 kg of copper} = 5.56 \text{ grams} \times 1000 \text{ grams} = \frac{100 \times 1000}{18} \text{ grams} \approx 5555.56 \text{ grams} \]

4. **Convert Grams to Kilograms**:
- To convert grams to kilograms, we divide by 1000:
\[ \text{Mixture in kg} = \frac{5555.56 \text{ grams}}{1000} \approx 5.56 \text{ kg} \]

5. **Final Answer**:
- Therefore, the amount of mixture required to obtain 1 kg of copper is approximately 5.56 kg.

### Summary:
To obtain 1 kg of copper from a mixture that contains 18% copper by weight, you need approximately 5.56 kg of the mixture.