## 62. Math Puzzle $7 / 70$

Two trains pass each other in opposite directions. One travels at a speed of $36 \frac{\mathrm{km}}{\mathrm{h}}$, the other at $45 \frac{\mathrm{km}}{\mathrm{h}}$. A passenger in the second train noticed that the first train took 6 s to pass him.

How long was the train?