7. (10 points) On the way from home to school, Xiaolong passes a store and a playground. The distance from home to the store is 500 meters, which took 7 minutes; from the store to the playground, he walks at a speed of 80 meters/minute for 8 minutes; the distance from the playground to school is 300 meters, and he walks at a speed of 60 meters/minute. What is Xiaolong's average speed from home to school in meters/minute?
【Analysis】First, according to the formula: distance $=$ speed $\times$ time, multiply the speed from the store to the amusement park by the time used to find the distance from the store to the amusement park, and then find the distance from Xiaolong's home to the school; then, according to the formula: time $=$ distance $\div$ speed, divide the distance from the amusement park to the school by Xiaolong's walking speed to find the time used from the amusement park to the school; finally, divide the distance from Xiaolong's home to the school by the time used to find the average speed from Xiaolong's home to the school.

【Solution】Solution: $(500+80 \times 8+300) \div(7+8+300 \div 60)$
$$
\begin{array}{l}
=(500+640+300) \div(7+8+5) \\
=1440 \div 20 \\
=72 \text { (meters/minute) }
\end{array}
$$

Answer: Xiaolong's average speed from home to school is 72 meters/minute.
Therefore, the answer is: 72 .