Talk:Rampage of Doomfire - Pompeii/@comment-16894369-20180510171544

Chance is revealed to be 0.8%, according to Official News. After 30 draws, the chance for getting Pompeii will increase for every draw until the 40th draw, which will be guaranteed. Previous black diamonds probably has the same chance as well, but that's beside the point.

With this calculation, it is pretty clear that the chance of getting Pompeii within 30 draws is 1 - (0.992)^30 = 0.2143...... Therefore, 78.57% of the time you will find yourself having to draw 10 more after spending 150 diamonds.