
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
The total mass ratio of two oil barrels, A and B, including their oil, is $4:5$. After pouring 8 kg of oil from barrel B into barrel A, the total mass ratio of barrel A and barrel B, including their oil, becomes $8:7$. Given that the mass of each barrel is 10 kg, find the original mass ratio of the oil in barrels A and B.

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