A box contains 8 red and 5 blue balls. Two balls are taken one after the other without putting the first back. Find the probability that both are red.
Answer and explanation
Correct answer: B.
- Step 1: First ball red: ; second ball red: . Step 2. . **Answer: . Why not the others:** is what you get if you put the first ball back. is what you get if you ignore the second draw. is what you get if you keep the total at for the second ball.
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