## Task 2 - 070912

Let $x$ be a (in the decimal system) six-digit number that ends with the digit 5. If this digit is moved from the sixth position to the first position, placing it in front of the unchanged five remaining digits, the resulting six-digit number is four times as large as $x$.

What is the number in the decimal system?
Let $y$ be a five-digit number ($f$ digits to be found). It is $x=10 y+5$. Then we have:

$$
4 \cdot(10 y+5)=500000+y \quad \rightarrow \quad 39 y=499980 \quad \rightarrow \quad y=12820
$$

Thus, the number in the decimal system is 128205.