Question

A box contains 3 green balls and 9 blue balls. Two balls are selected at random one after the other without replacement. What is the probability that the second one is blue?

Answer 1

17/22

Answer 2

Average the 2 probabilities post 1st removal.

Answer 3

It says the answer is 1/3

Answer 4

Can you figure out the probability of getting a blue ball on the first pull?

Answer 5

Wouldn't it be 9/12?

Answer 6

Okay, good. Now, the ball is not being replaced, so you know there are only 11 balls on the second pull. Right?

Answer 7

Yes