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A bag contains 5 white and 3 black balls. Two balls are drawn at random one after another without replacement. What is the probability that the second ball is white given that the first ball drawn was black?

  1. 57\frac{5}{7}

  2. 58\frac{5}{8}

  3. 38\frac{3}{8}

  4. 27\frac{2}{7}

Show answer & explanation

Correct answer

57\frac{5}{7}

Explanation

After first black, remaining: 5 white, 2 black (total 7). Probability second is white = 5/7.

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All 30 Probability questions

  1. 1.A bag contains 4 red balls and 6 blue balls.
  2. 2.A die is rolled once.
  3. 3.A coin is tossed twice.
  4. 4.A card is drawn from a well-shuffled deck of 52 cards.
  5. 5.A box contains 3 red, 5 green, and 2 yellow balls.
  6. 6.What is the probability of getting a sum of 7 when two dice are rolled together?
  7. 7.In a class, there are 15 boys and 10 girls.
  8. 8.A spinner has 8 equal sections numbered 1 to 8.
  9. 9.A bag contains 5 red and 7 black balls.
  10. 10.If P(A) = 0.4 and P(B) = 0.5 for independent events A and B, what is P(A B) ?
  11. 11.A bag contains 4 red, 5 blue, and 6 green balls.
  12. 12.In a box, there are 3 defective and 7 non-defective items.
  13. 13.A card is drawn from a well-shuffled deck of 52 cards.
  14. 14.Two dice are rolled simultaneously.
  15. 15.A speaks truth in 75% cases and B speaks truth in 80% cases.
  16. 16.A bag contains 5 white and 3 black balls.
  17. 17.From a group of 6 men and 4 women, a committee of 3 persons is to be formed.
  18. 18.The probability that a student will pass in Mathematics is 0.6 and that in English is 0.5.
  19. 19.A die is thrown twice.
  20. 20.In a lottery, there are 5 prizes and 20 blanks.
  21. 21.A fair coin is tossed 5 times.
  22. 22.Two fair dice are rolled together.
  23. 23.Three fair dice are rolled simultaneously.
  24. 24.Two cards are drawn successively without replacement from a well-shuffled standard deck of 52 cards.
  25. 25.From a well-shuffled standard deck of 52 cards, 3 cards are drawn at random simultaneously.
  26. 26.An urn contains 6 white, 5 black and 4 red balls.
  27. 27.An urn contains 7 red and 5 blue balls.
  28. 28.For two events A and B, P(A) = 0.5 , P(B) = 0.4 and P(A B) = 0.2 .
  29. 29.For two events A and B, P(A) = 0.45 , P(B) = 0.35 and P(A B) = 0.15 .
  30. 30.In an examination, 70% of the students who pass actually know the material, while the remaining 30% pass purely by guessing.