
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
A farmer decides to divide his herd of cows among his four sons. He gives the first son $\frac{2}{5}$ of the herd, the second son $\frac{1}{5}$, and the third son $\frac{1}{10}$. The remaining cows go to the fourth son, who receives 9 cows. What is the total number of cows in the farmer's herd?
A) 28 cows  
B) 30 cows  
C) 32 cows  
D) 34 cows

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