Answer: 1/4
In other words, the number 4 goes in the green box.
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Explanation:
2 yellow + 3 pink + 5 blue = 10 total marbles
We have 5 blue out of 10 total, so 5/10 = 1/2 represents the probability of picking a blue marble.
Picking two marbles in a row is represented by the probability (1/2)*(1/2) = 1/4
The fraction 1/2 stays the same for both selections because we put the first marble back.
