
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
Given that a grain and oil store needs to purchase 900 tons of cooking oil per year, with each purchase being $x$ tons at a shipping cost of 3,000 yuan per time and a total annual storage cost of $3x$ thousand yuan, find the value of $x$ that minimizes the sum of the total shipping cost and the total storage cost for the year.

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