Task B-1.1. In a three-digit number, the hundreds digit is 3. If it is moved to the units place, the resulting number is $75\%$ of the original number. What is the number?
First solution. The desired number is of the form $\overline{3 x y}=300+10 x+y$. The given condition can be written as

$$
\begin{aligned}
\overline{x y 3} & =0.75 \cdot \overline{3 x y} \\
100 x+10 y+3 & =\frac{3}{4}(300+10 x+y) \\
\frac{185}{2} x+\frac{37}{4} y & =222 / \cdot \frac{4}{37} \\
10 x+y & =24
\end{aligned}
$$

It follows that $\overline{x y}=24$ so $\overline{3 x y}=324$ and this is the desired number.

(1 point)