
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system

There are two docks, $A$ and $B$, on a river, where dock $A$ is upstream and dock $B$ is downstream. There are two boats, Boat 1 and Boat 2. The speed of Boat 1 in still water is twice the speed of Boat 2. Both boats start simultaneously from docks $A$ and $B$, respectively, and move towards each other. When Boat 1 departs, it leaves a floating cargo box on the water. After 20 minutes, the two boats meet and Boat 1 leaves another identical cargo box on the water. A while later, Boat 1 notices that it is missing cargo and turns around to search for it. When Boat 1 finds the second cargo box, Boat 2 encounters the first cargo box. Determine how many minutes have passed since Boat 1 departed when it realizes its cargo is missing. (Assume the time for turning around is negligible.)

Present the answer in LaTex format: \boxed{Your answer}
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