Question

A jar has 3 red marbles and 9 blue ones. If you randomly pick a marble without replacing it and then select another, what is the fractional probability of getting 2 blue?

Answer 1

Well if the person picked a blue marble the first time that would have been a 1/3 chance the 1 would be the blue marble and the 3 would be the red.

if they then picked another marble it would have been again 1/3 assuming that they had picked a blue marble, to begin with

i hope this makes sense to anyone really  (cuz it did in my mind)  ;)

Answer 2

The probability of picking two blue would be 2/9 because you would use the 2 out of the 9