
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
In a bag, there are 10 red balls and several yellow balls. Without the option to pour out and count the balls, Xiao Ming adopted the following method to estimate the number of yellow balls in the bag: Each time, he would draw 10 balls from the bag, calculate the ratio of the number of red balls to 10, then put the balls back into the bag and mix well. This process was repeated 20 times, and the average ratio of the number of red balls to 10 was found to be 0.4. Based on the data, estimate the approximate number of yellow balls in the bag.

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