Activist: The average CEO is paid many times more than the average worker is paid at the same company.
Evidence
It is certain that no CEO works many times harder than the average worker.
Conclusion (Therefore)
The high pay of CEOs is wholly unjustified.
Evaluate
It's fine to consider the first sentence as part of the evidence, but it's really giving us an idea of how high the average CEO's pay is when compared to the average worker. If anything, we might bake this information into the conclusion:
It is wholly unjustified to pay CEOs many times more than the average worker at their company is paid.
In order for the evidence to fully support this conclusion, we need to assume that, if a CEO does not work many times harder than the average worker at their company, it is wholly unjustified to pay the CEO many times more than the average worker is paid.
We could even diagram this:
~work many times harder → ~pay many times higher
Goal
Since this is a Principle-Strengthen question, the correct answer might contain this exact assumption. However, the correct answer only needs to strengthen the argument. A principle which states something like, would be good enough. Beware of answers that contain illegal reversals or illegal negations of the assumption we identified above.