The total length of road is 1000 km. When someone drives, the average speed of the first 400 km is 200 km/h, and the average speed of the last 600 km is 150 km/h. What is the average driving speed of this whole trip?
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A166.67 km/h
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B180 km/h
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C200 km/h
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D210 km/h
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E230 km/h
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正确答案: A