9. There is a road between the gymnasium and the school, and it takes 30 minutes for a car to travel back and forth. One day, a basketball game ended at 4 PM, and the students immediately walked back to the school along the road. On the way, they encountered a car that left the school at 4:30 PM to pick them up. They immediately got into the car and arrived at the school at 4:50 PM. How many times faster is the car's speed compared to the students' walking speed?
【Answer】8
【Analysis】Key point: Travel problem
The car takes the same time for both ways: $(50-30) \div 2=10 \mathrm{~min}$; The student meets the car at $4: 40$; The student has walked one-third of the distance in $40 \mathrm{~min}$; The car takes $10 \mathrm{~min}$ to cover two-thirds of the distance; The car takes $5 \mathrm{~min}$ to cover one-third of the distance; The car's speed is $40 \div 5=8$ times the walking speed.