You have three types of Picnic Egg Boxes; the Golden Deluxe which contains three gold eggs and one plain, the Regular which contains two gold eggs and two plain and the Econolunch which contains one gold egg and three plain. You go to the corner store and buy a Picnic Egg Box at random, and select an egg from it at random. The egg is gold! Use a probability tree diagram to calculate the probability that the box you bought was a Regular.

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