7. (3 points) A fast train takes 5 hours to travel from location A to location B, while a slow train takes $\frac{1}{5}$ more time to travel from location B to location A. If both trains start from their respective locations and travel towards each other, after 2 hours, the slow train stops. The fast train continues to travel another 40 kilometers and meets the slow train exactly. The distance between locations A and B is $\qquad$ kilometers.
【Solution】Solution: The time required for the slow train to complete the entire journey is:
$$
\begin{array}{l}
5 \times\left(1+\frac{1}{5}\right), \\
=5 \times \frac{6}{5}, \\
=6 \text { (hours); }
\end{array}
$$

The entire distance is:
$$
\begin{array}{l}
40 \div\left[1-\left(\frac{1}{5}+\frac{1}{6}\right) \times 2\right], \\
=40 \div\left[1-\frac{11}{15}\right], \\
=40 \div \frac{4}{15}, \\
=40 \times \frac{15}{4}, \\
=150 \text { (km); }
\end{array}
$$

Answer: The distance between locations A and B is 150 km.
The answer is: 150.