【Question 18】
There are two cars leaving the station one after another heading to the dock. The speed of the first car is 90 kilometers per hour. At 8:32, the distance of the first car from the station is 1.2 times the distance of the second car from the station; by 9:20, the distance of the first car from the station is twice the distance of the second car from the station. If the first car left the station at 8:08, how many kilometers per hour does the second car travel?
【Analysis and Solution】
$8: 32$, the first car has traveled $90 \times \frac{24}{60}=36$ kilometers, the second car is $36 \div 1.2=30$ kilometers away from the station;
$9: 20$, the first car has traveled $90 \times 1 \frac{12}{60}=108$ kilometers, the second car is $108 \div 2=54$ kilometers away from the station; the second car travels $(54-30) \div \frac{48}{60}=30$ kilometers per hour.