Card probability problem

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I located the adhering to trouble in Rosen is Discrete Mathematics and also Its Applications 6th ed. :

There are 3 cards in a box. Both sides of one card are black, both sides of one card are red, and also the 3rd card has one black side and also one red side. We select a card randomly and also observe just one side.

If the side is black, what is the probability that the opposite side is additionally black?

Should not the response to the inquiry be $1/3$, as amongst $3$ cards just $1$ of them has both sides black. Yet guide claims solution is $2/3$, do I miss out on anything?

2022-07-25 20:47:14
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