(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

An urn contains four colored balls: two orange and two blue. Two balls are selected at random without replacemen, and you are told that at least one of them is orange. What is the probability that the other ball it orange?

2. Relevant equations

Now, we have been studying P(A|B) meaning the probability of A given the B has already happened.

3. The attempt at a solution

Now, my book ends up with a solution of 1/5. But I have no idea how. I said since you know that one of the balls is definitely orange, then you have 3 balls to choose from. So if I want to do it technically (1C1) / (3C1) = 1/3 (C stands for the combination) . However, it's just a quite logical problem in my opinion.

So who is correct? Me or the book? Thanks! I would love to know how to get 1/5 if I am wrong.

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Conditional probability drawing two balls from an urn.

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