I have been farming Coercer Q`ioul (25% drop rate) and Advisor C`zatl (24.5% drop rate) according to MQEmu and after 10 kills each 0 kedge robe drops. If my math is correct I should have a 50% drop per clear of them both leading to a 500% chance after 10 clears for 1 drop. Is my math off or bad rng? or something else?
Bad math. 2 chances at 25% != 50% Chance. Bad luck too tho, I have wiped that hut out 6-7 Times and seen 3 Kedge robes. You're currently sitting at around a 5% chance of 2 events not happening at 25% probability of each. Basically you rolled a crit on a d20, but for bad luck, not good. Check out probability calculators and equations if you want to figure out the math.
Yeah, the drops are entirely independent so you can't really say that. All you can really say is that with enough samples it will drop 1/4 the time.