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.