
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 split his herd of cows among his four sons. The first son is to receive $\frac{1}{3}$ of the herd, the second son $\frac{1}{6}$, the third son $\frac{1}{7}$, and the rest goes to the fourth son. If the fourth son receives 15 cows, determine the total number of cows in the herd.
A) 70
B) 42
C) 84
D) 56

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