# Statistics: Probability card colour

There are three cards. The first is green on both sides, the second is red on both sides and the third is green on one side and red on the other. We choose a card at random and we see one side (also at random). If the side we see is green, what is the probability that the other side is also green? Many people intuitively answer 1/2. Show that the correct answer is 2/3.

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#### Solution Preview

The probability that the other side is green is 2/3 because one you see the first green side, there's a 2/3 chance you're looking at the green/green card. Since the first time you look at a card, you also choose a random side to look at, you have an equal chance of looking at any of the 6 total sides (3 cards * 2 sides/card). Three of these 6 chances are green. Two of the 3 ...

#### Solution Summary

Solution provides steps necessary to calculate the probability.