A bag holds 3 red and 5 blue balls. Two balls are drawn one after the other without replacement. What is the probability that both are red?
Answer and explanation
Correct answer: A. 3/28
- Step 1: The first draw is red with probability 3/8. Step 2. Then 2 red remain among 7 balls, so the second draw is red with probability 2/7; the product is 6/56 = 3/28. Answer: 3/28. Why not the others: 9/64 would be correct with replacement; the others ignore the changing bag.
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