Xiaoqiang and Xiaojun set out at the same time from a and B, 80 meters apart. They kept walking back and forth between ab. it is known that Xiaoqiang walked 8 meters per minute and Xiaojun walked 10 meters per minute. They kept walking for two hours. How many times did they meet?

This seems to be very difficult, but it's not difficult. You think, the two of them always meet once when they walk 80 meters, and then run in opposite directions. It's equal to one round, that is, meeting once when they walk 160 meters (you can imagine it slowly). In two hours, they walk 18x120 / 160 = 27, so they meet 27 times in total

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