
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
Digging a well 21 meters deep, it takes 40 minutes to reach the first meter in depth. From the first meter to the second meter, it takes 50 minutes, and for each additional meter in depth, it takes 10 minutes more than the previous meter. How many hours does it take to dig to the last meter?

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