Tres amigas, again.
Probability
Level
3
A bag contains 10 red and 10 blue marbles.
- Ella takes a marble from the bag (without looking) and puts it in her pocket.
- Next Bella takes a marble from the bag.
- Finally Frabduzella takes a marble from the bag.
Bella and Frabduzella have the same color marble.
What is the probability that Ella's marble is red?
Follow-up to this problem
The answer is 0.5.
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The answer is symmetric w.r.t both blue and red, thus both their probabilities are same and add up to unity. Thus, P = 0.5