# probability regarding balls

#### raindoe

##### New member
Hi guys, I have a maths question about Probability, hope somebody can help me out, thank you very much.

There are 5 red, 4 blue and 3 green balls in a bag. Two balls are taken from the bag, one after the other. If the first ball is not replaced, and it was not green. What is the probability that:

a) both balls are red?
b) at least one ball is green?

#### Country Boy

##### Well-known member
MHB Math Helper
Hi guys, I have a maths question about Probability, hope somebody can help me out, thank you very much.

There are 5 red, 4 blue and 3 green balls in a bag. Two balls are taken from the bag, one after the other. If the first ball is not replaced, and it was not green. What is the probability that:

a) both balls are red?
b) at least one ball is green?
a) There are a total of 12 balls in the bag, 3 of them red. What is the probability the ball drawn is red? If the first ball is red there are 11 balls left, 2 of them red. What is the probability the second ball is also red? So what is the probability they are both red?

b) You are told that the first ball drawn is "not green". "At least one ball is green" requires that the second ball also be green. There are 11 balls left. What is the probability the second ball is "green"?

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