I have 30 balls (aiii), 27 of them are blue and 3 of them are red. I put all these balls in a bag and pick out 10 without replacement. What the change that one or more of the red balls will be in this selection.
It should be soooo easy, but I'm having huge problems getting my head around it. (my latest answer is about 0.72)
Answers and solutions in the comments please :)