## Arkham Horror probability problem

Hello everyone!

So yesterday my friends and I were playing a good game of arkham horror. As we were playing, I pointed out that one of my favorite weapons to use (in the base game alone) was the shotgun. Always seem to blow apart my foes in ease with a blessing on hand, passing the Will checks, with +1 Fight skill, and 6's keep coming out for the double successes.

One of the other guys who's never played before last night felt the urge to say/argue that the chances of killing the same said monster with a blessing, passing the will check, with the same combat rating, the +1 Fight skill, but with a pair of enchanted blades is the better option in an equal setting. So, since I was not able to sleep tonight and being a former 40k player, I decided to "mathhammer" it out between the two controlled scenarios against a really tough monster to determine the better combo. Problem is, I crunched the math (which is all over the place and I am starting to get tired) and I think I made errors. If someone could give me a hand that would be great, so I can check my work and share with him my results (cause there's no worse thing than arkham players with bad blood between them playing again) so this can put my mind at ease. Here's what I have:

Target Monster: Has a combat rating of -3 and 3 toughness.

Character: Fight rating base is 3, +1 fight from skill (no clue tokens for rerolls), and a blessing (4+ to succeed).

Note: We assume Will check was passed.

Here's my math work:

Scenario #1: Dual Enchanted Blades (+4 combat each).
-> Total combat dice= (3+1+4+4)-3= 9d6
-> Combat chances minus toughness:
=>(3/6)^9 -(3/6)^3= .00195-.125= -0.1269

Scenario #2: Single Shotgun (+4 combat and each 6 rolled is a double success)
-> Total combat dice= (3+1+4)-3= 5d6
-> Combat chances minus toughness:
=>[(3/6)^5+ (1/6)^5] - (3/6)^3= (.07776+.00013)- 0.125= 0.07788- 0.125= -0.04712

So I don't think my math makes much sense at this point (negative values?) and I bet I'm missing steps or forgetting things I need to do (like accounting for the 6's for the shotgun correctly). It's been a while since I've done things like this in my gaming days, plus I haven't taken probability in so long, but it would be nice to know. Sorry if I make anyone else's brain hurt too, cause now I need sleep.

What am I missing or not understanding? :confused: