Question 23508
i have a lesson on probability on this site. Go and read it.


Anyway, to answer you, without much explanation:


P(BB) = P(first B) AND P(second B)
P(BB) = 5/9 * 4/8


Once we select the first blue and do not replace it, we are left with the urn holding 4 red and 4 blue... hence the second fraction in my calculation.


P(BB) = 5/9 * 1/2
P(BB) = 5/18


jon.