One person said to the other: Give me 7 denars, then I will be 5 times richer than you. The other replied: Rather, you give me 5 denars, then I will be 7 times richer than you. How much money did each of them have?
The solution to the task is not an integer, so several people noted that sharing is only possible with appropriate change.

The interesting thing about the task is that it comes from Leonardo Pisano, better known as Fibonacci (1175-1250), more than 700 years ago. The text can be found on page 124 of the book "Mathematical Historical Problems" by Dr. Lévárdi László and Sain Márton. We don't know what currency they used at that time, but we accepted as solutions $7 \frac{2}{17}$ and $9 \frac{4}{17}$ denarii.