William W. answered • 11/09/21

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There are a total of 12 notebooks with 3 of them being green. After he pulls out 2, there are 10 remaining. Since the probability that one of those 10 is green is 2/10 then there MUST be 2 green among the 10 total. That means ONE of the original two drawn must be green. However, you do not know anything about the other notebook except that it is not green (only one of the two originally drawn must be green).

This does not match with any of the answers you provided.

You only know one of the original two drawn is green. The other could be yellow, could be blue, or could be red.