A cyclist travels from town A to town B at a constant speed of 20 miles per hour. On the return trip from town B to town A, he increases his speed by 10 miles per hour and makes the trip in 2 hours less than the trip from A to B. If the total round trip distance is 180 miles, what is the distance between town A and town B? Let's think step by step and output the final answer within \boxed{}.
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