A bag has 2 red and 3 blue marbles. Two marbles are drawn one after the other without replacement. What is the probability that both are red?
Answer and explanation
Correct answer: B.
- Step 1: The first marble is red with probability 2/5.
- Step 2: Then 1 red marbles remain among 4, so the probability is after multiplying.
Answer
.
Why not the others: With replacement the second probability would stay the same; adding probabilities is not correct for two events that must both happen.
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