13.149. Find two numbers whose sum is 44, with the smaller number being negative. The percentage ratio of the difference between the larger and smaller numbers to the smaller number coincides with the smaller number.
Solution.

Let $x$ and $y$ be the required numbers $(y<0)$. Then $\left\{\begin{array}{l}x+y=44, \\ \frac{x-y}{y} \cdot 100=y,\end{array}\right.$ from which $x=264, y=-220$.

Answer: -220 and 264.