Exploit Weakness (Ex)
At 4th level, as a swift action, a martial artist can observe a creature or object to find its weak point by making a Wisdom check and adding his monk level against a DC of 10 + the object’s hardness or the target’s CR. If the check succeeds, the martial artist gains a +2 bonus on attack rolls until the end of his turn, and any attacks he makes until the end of his turn ignore the creature or object’s DR or hardness. A martial artist may instead use this ability as a swift action to analyze the movements and expressions of one creature within 30 feet, granting a bonus on Sense Motive checks and Reflex saves and a dodge bonus to AC against that opponent equal to 1/2 his monk level until the start of his next turn.
This ability replaces ki pool.
My question is in the line "by making a Wisdom check and adding his monk level against a DC of 10 + the object’s hardness or the target’s CR."
Is that:
DC 10 + the object's hardness or the target's CR. (If the object's hardness is 5 the CR of the check is 15. If the creature's CR is 5 the DC of the check is 15)
or
DC 10 + the object's hardness, or the target's CR. (If the object's hardness is 5 the CR of the check is 15. If the creature's CR is 5 the DC of the check is 5)
It is the first. 10 + objects hardness or 10 + creatures CR. 15 or 15.
The first.
However I have no evidence, other than if it were the second case any relevant CR would be autopass, which doesn't seem logical.
Agreeing with previous posters (and editing a misread).
So if the target is an object, the DC is 10+hardness.
If the target is a creature, the DC is 10+CR.
So, the first one.