Percoset is oxycodone + acetaminophen.
Norco is hydrocodone + acetaminophen.

Oxycodone is 1.5 times more strong than hydrocodone.
If you have 5mg of Percoset, it is as if you took 7.5mg of hydrocodone.

So, in your (most recent) example, which is stronger, 10mg of Percoset or 10mg of Norco?

The Percoset would be more strong. 10mg of it would be like taking 15mg of Norco.

Gee, and I thought I never understood those algebra word problems!