A dishonest dealer sells the goods at 15% loss on cost price but uses false weight. So his over all profit is 25% find the gm. In 1 kg. that he used.

Answer

To solve the problem step by step, we need to find out how many grams the dishonest dealer uses instead of 1 kg (1000 grams) while still achieving an overall profit of 25% despite selling at a 15% loss on the cost price.

### Step-by-Step Solution:

1. **Understand the Loss and Profit**:
- The dealer sells goods at a 15% loss on the cost price (CP).
- This means if the cost price is 100, he sells it for:
\[ \text{Selling Price (SP)} = \text{CP} - \text{Loss} = 100 - 15 = 85 \]

2. **Calculate the Overall Profit**:
- The dealer has an overall profit of 25%. This means if he had a cost price of 100, his selling price should be:
\[ \text{SP} = \text{CP} + \text{Profit} = 100 + 25 = 125 \]

3. **Determine the Effective Selling Price**:
- The dealer sells at a loss of 15%, which means he sells the goods for 85 (as calculated in step 1). However, he wants to achieve a selling price that gives him a 25% profit based on the cost price.
- To find out how much he actually sells in terms of grams, we need to set up a proportion.

4. **Set Up the Equation**:
- Let \( x \) be the actual weight (in grams) that he sells instead of 1000 grams.
- The relationship can be set up as:
\[ \frac{20x}{17,000} = \frac{4}{5} \]
- Here, 20 represents the total units (1000 grams) and 17,000 is the effective selling price he receives for that weight.

5. **Cross Multiply and Solve for x**:
- Cross-multiplying gives us:
\[ 5 \times 20x = 4 \times 17,000 \]
\[ 100x = 68,000 \]
\[ x = \frac{68,000}{100} = 680 \]

6. **Conclusion**:
- The dealer uses 680 grams instead of 1 kg (1000 grams) to achieve an overall profit of 25%.

### Final Answer:
The dishonest dealer uses **680 grams** instead of 1 kg.