Someone wanted to gift 6 liters of wine from a 12-liter jug that is full of wine. However, they only have a 7-liter and a 5-liter jug for measuring. How can they fill the 7-liter jug with 6 liters of wine?
The following table shows a solution:

| 12-letter | 7-letter | 5-letter |
| :---: | :---: | :---: |
| 12 | 0 | 0 |
| 5 | 7 | 0 |
| 5 | 2 | 5 |
| 10 | 2 | 0 |
| 10 | 0 | 2 |
| 3 | 7 | 2 |
| 3 | 4 | 5 |
| 8 | 4 | 0 |
| 8 | 0 | 4 |
| 1 | 7 | 4 |
| 1 | 6 | 5 |
| 6 | 6 | 0 |

(György Ballai, Budapest.)

Number of solutions: 12.