To solve the problem of how many kilograms of tea worth 300 rupees per kilogram should be mixed with 10 kilograms of tea worth 240 rupees per kilogram to achieve a mixture costing 260 rupees per kilogram, we can apply the concept of weighted averages.
Let’s denote:
- x: the number of kilograms of tea at 300 rupees per kg.
- 10 kg: the amount of tea at 240 rupees per kg.
1. **Calculate the total cost of each type of tea:**
- Cost of x kg of tea at 300 rupees = 300x
- Cost of 10 kg of tea at 240 rupees = 2400 (since 240 * 10 = 2400)
2. **Calculate the total mass of the mixture:**
The total weight of the mixture will be x + 10 kg.
3. **Set up the equation for the cost of the mixture:**
The mixture should have an average cost of 260 rupees per kg, so:
(300x + 2400) / (x + 10) = 260
4. **Cross-multiply to solve for x:**
300x + 2400 = 260(x + 10)
Expanding this gives:
300x + 2400 = 260x + 2600
5. **Rearranging the equation:**
Now, we can simplify this:
300x - 260x = 2600 - 2400
This simplifies to:
40x = 200
6. **Solving for x:**
x = 200 / 40
This gives us:
x = 5
7. **Conclusion:**
You need to mix 5 kilograms of tea worth 300 rupees per kilogram with the 10 kilograms of tea worth 240 rupees per kilogram to achieve a desired mixture costing 260 rupees per kilogram.