Probability

No.11833172 ViewReplyOriginalReport
Are you good at DnD?
Are you good at math?
If you answered "yes" for at least one of those, maybe you can help me, because I can't.

I'm playing a multiclass character that is a fighter and also a warlock, I have the Elven Accuracy feat that allows me to play three dices to attack when I have advantage, I also can curse my target so 19 rolls will also be criticals, I have two attacks per round, but I also can use the feature "Action Surge" to gain more two attacks, four in total.

So, this is if you don't play DnD, before attacking an enemy, I roll a 20 sided dice to check if my hit will land, if the dice rolls 20, then I get a critical hit, if it rolls 19, I get a critical as well, which, at least in my mind, gives me a 2/20 (10%) of getting a critical hit, but I can roll three times and choose the best dice, so I guess I have (2+2+2)/20, or 6/20, now I must remember you that I have the second attack, which would give me three more chances to roll, so 12/20. But, then again, I can gain two more attacks, thus becoming 24/20, which would, theoretically, certainly hit a critical blow.

I know I'm wrong, I don't know why and where I got myself confused with those numbers. If you are willing to explain me, please, treat me as a child, but any internet video helping me with the question would also be really helpful. Someone once said to me that to get the right result, I must calculate the chances of NOT hitting 19 or 20, but I have no idea how to do that.

Thank you!