Board Thread:Questions and Answers/@comment-68.226.81.85-20150111205650/@comment-25968376-20150111212431

The percentages for items don't stack. You can think of having more of them as having a chance of redraw for every item.

So if you have an item with 30% chance of getting a crystal and you get one more of the item, you won't have a 60% chance to get a single crystal. If my math-fu serves me right (someone please correct me if I'm wrong), you could end up with the following combinations:

- gain from both items, i.e. 2 crystals (probability 0.30*0.30 = 9%)

- gain from the first item but not the second, i.e 1 crystal (probability 0.30*0.70 = 21%)

- gain from the second item but not the first, i.e. 1 crystal (as above)

- gain nothing from either (probability 0.70*0.70 = 49%)