A bag contains five white balls and five black balls. Your goal is to draw two black balls.
You draw two balls at random. Once you have drawn two balls, you put back any white balls, and redraw so that you again have two drawn balls. What is the probability that you now have two black balls? (Include the probability that you chose two black balls on the first draw.)
I have not worked this question out but I would most likely look at the different probabilities and then add them together
P(BB)
+ P(WW throw back and get BB) on second try)
+ P(BW throw back the white one and get a black next time)
+ P(WB throw back the white one and get a black next time)