10. As shown in the right figure, a rectangular prism with length, width, and height of $15,5,4$ has a piece with length, width, and height of $y, 5, x$ cut away $(x, y$ are integers). The remaining volume is 120. Find $x$ and $y$.
【Answer】 $x=3, y=12$
【Solution】
$$
15 \times 5 \times 4-y \times 5 \times x=120
$$

Solving, we get $xy=36; 36=1 \times 36=2 \times 18=3 \times 12=4 \times 9=6 \times 6$. Since $x, y$ are integers, and $x<4, y<15$, thus $x=3, y=12$.