
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
An empty swimming pool was filled with water by two taps \(A\) and \(B\), both with constant flow rates. For 4 hours, both taps were open and filled 50% of the pool. Then, tap \(B\) was closed and for the next 2 hours, tap \(A\) filled 15% of the pool's volume. After this period, tap \(A\) was closed and tap \(B\) was opened. How long did tap \(B\) need to remain open to fill the pool by itself?

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