A car travels from point A to point B at an average speed of 60 km/h. After reaching point B, the car immediately returns to point A along the same route at an average speed of 40 km/h. If the total distance traveled (from A to B and back to A) is 200 km, what is the average speed of the car for the entire trip? Let's think step by step and output the final answer within \boxed{}.
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