Three friends, Alice, Bob, and Charlie, decide to meet at a park. Alice lives three-fourths of a mile from the park, Bob lives half a mile farther from the park than Alice, and Charlie lives twice as far from the park as Bob. If Alice, Bob, and Charlie each start walking towards the park at the same time, what is the total distance they collectively cover to reach the park? Let's think step by step and output the final answer within \boxed{}.
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