Sam wants to craft a Hellfire ring. He has three Infernal Machines, and only needs one more organ to craft it.

At MP5 (50%) drop-rate, what are the chances that he will get that particular drop?

There is obviously three possible portals, and a 50/50 drop rate once the correct portal opens - so even if he ends up using all three machines (the last used opening the correct portal), the

*worst*the odds can be is 50/50. But the correct portal

*could*theoretically be opened three times (all on the first try, albeit in different games).

So, what are the odds that three Infernal Machines will be parlayed into the last required organ?

There is an algebraic solution.

**Show your work.**

07/22/2013 07:15 AMPosted by Garthandal50/3=16.6%

No. Not even close. If he had a single Infernal Machine the odds would be:

1/3 x 1/2 = 1/6

But he has three, so at worst the odds are...

1 x 1/2 = 1/2

What are his

*best*odds? Anyone?

50%

1-((1-0.5)^1) = 0.5

50% Chance

For 2 portals:

1-((1-0.5)^2) = 0.75

75% Chance

For 3 portals:

1-((1-0.5)^3) = 0.875

87.5% Chance

I can't believe no one has gotten it yet.

Another poster had the formula right but the answer wrong.

Edit: 5.5% was not the right answer. I was thinking .55% (which was close but still wrong).

This is a trick question.

Sam's gear is too bad to do Ubers, and so he effectively has a 0% chance.

Sam's gear is too bad to do Ubers, and so he effectively has a 0% chance.

doing it in 1 Portal he has a chance of 50%.

doing it in 2 Portal he has a chance of 50% in the first portal, and 25% (50% of a 50% chance) in for the second portal. so -> 75%

doing it in 3 Portals means: 50% + 25% + 12.5%. so the one with 87.5% was right

Come pm for your prize Azaroth

1 game three portals: 1/2 = 50%

3 games 1 portal: 3*(1/3)/2 = 50%

3 games 1 portal: 3*(1/3)/2 = 50%

but then you dont calculat in the chance to get all the right portals in the first try?

07/22/2013 07:46 AMPosted by Azarothbut then you dont calculat in the chance to get all the right portals in the first try?

I thought it was 66% at first.

.33 / .50 = .66%

But I figured Azaroth put so much time into the equation I would go ahead and give him the prize.

It may actually be .66% - or it may be .50%...I don't know myself anymore!

*note to self, think your questions through a little more before creating threads*