From the station in front of Xiaohong’s house to the school, there are two kinds of buses, No. 1 and No. 9. They both come every 10 minutes. When Xiaohong arrives at the station, as long as she sees No. 1 or No. 9, she will get on immediately. Cars, according to someone's observations, it is always found that the No. 9 bus comes 3 minutes after the No. 1 bus, and the No. 1 bus comes 7 minutes after the No. 9 bus passes. How many cars is it possible for Xiaohong to take? (Write out the idea of solving the problem)
从小红家门口的车站到学校，有1路和9路两种公共汽车可乘，它们都是每隔10分钟来一辆，小红到车站后，只要看见1路或9路，马上就上车，据有人观测发现；总是1路车过去3分钟就来9路车，而9路车过去以后7分钟才来1路车，小红乘多少路车的可能性比较大？(写出解题思路)
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