Two cyclists, Alice and Bob, start from the same point and ride in the same direction. Alice rides at a speed of 12 miles per hour, while Bob rides at a speed that is 3/4 of Alice's speed. If Alice takes a 30-minute break after 2 hours of riding, how far apart are Alice and Bob after 3 hours? Let's think step by step and output the final answer within \boxed{}.
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