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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 115 · 40 questions
TalentJR

How to solve it (Favourable over total): Probability = number of favourable outcomes ÷ total number of equally likely outcomes. List the outcomes: a dice has 6, two coins have 4 (HH, HT, TH, TT), three coins have 8, two dice have 36. Write the answer as a fraction in its lowest terms; a probability is never more than 1.

NameDateTime takenScore ___ / 40
  1. 1.A bag has 4 green, 6 white and 3 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 3/13 (b) 10/13 (c) 1/3 (d) 11/13
  2. 2.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 3/8 (b) 1/8 (c) 3/4 (d) 1/4
  3. 3.A bag has 9 blue, 2 green and 7 white balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/18 (b) 1/3 (c) 1/2 (d) 5/9
  4. 4.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
  5. 5.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/18 (b) 1/11 (c) 1/12 (d) 1/36
  6. 6.A fair dice is rolled once. What is the probability of getting a number greater than 4? (a) 1/2 (b) 1/6 (c) 1/3 (d) 2/3
  7. 7.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/12 (b) 2/11 (c) 1/18 (d) 1/11
  8. 8.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 5/6 (b) 2/3 (c) 1/4 (d) 1/3
  9. 9.A bag has 3 red, 8 white and 6 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 6/11 (b) 6/17 (c) 1/3 (d) 11/17
  10. 10.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/3 (b) 1/4 (c) 2/3 (d) 1/2
  11. 11.Three coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 5/8 (c) 3/5 (d) 3/8
  12. 12.A bag has 3 red, 5 yellow and 9 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 9/17 (b) 1/3 (c) 10/17 (d) 8/17
  13. 13.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/12 (b) 1/9 (c) 1/11 (d) 3/11
  14. 14.A bag has 3 red, 2 green and 6 blue balls. One ball is taken out without looking. What is the probability that it is not green? (a) 10/11 (b) 1/3 (c) 2/11 (d) 9/11
  15. 15.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 1/9 (b) 4/11 (c) 1/11 (d) 5/36
  16. 16.A bag has 6 blue, 3 red and 3 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 1/12 (c) 3/4 (d) 1/4
  17. 17.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 1/9 (b) 3/11 (c) 1/12 (d) 1/11
  18. 18.A bag has 8 green, 8 yellow and 3 blue balls. One ball is taken out without looking. What is the probability that it is not green? (a) 12/19 (b) 1/3 (c) 8/19 (d) 11/19
  19. 19.A bag has 5 red, 4 green and 9 yellow balls. One ball is taken out without looking. What is the probability that it is not green? (a) 1/3 (b) 7/9 (c) 2/9 (d) 5/6
  20. 20.A fair dice is rolled once. What is the probability of getting a number less than 5? (a) 1/4 (b) 1/3 (c) 2/3 (d) 5/6
  21. 21.Two coins are tossed together. What is the probability of getting at least one head? (a) 3/4 (b) 1/3 (c) 1/2 (d) 1/4
  22. 22.A fair dice is rolled once. What is the probability of getting a number greater than 1? (a) 1/5 (b) 1/6 (c) 1/3 (d) 5/6
  23. 23.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/6 (b) 1/3 (c) 1/2 (d) 2/3
  24. 24.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/2 (b) 1/3 (c) 1/6 (d) 2/3
  25. 25.A bag has 7 green, 7 blue and 9 red balls. One ball is taken out without looking. What is the probability that it is red? (a) 9/14 (b) 9/23 (c) 14/23 (d) 1/3
  26. 26.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 3/4 (b) 1/3 (c) 1/4 (d) 1/2
  27. 27.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 7/36 (b) 6/11 (c) 1/11 (d) 1/6
  28. 28.A bag has 3 red, 6 white and 4 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 4/13 (c) 9/13 (d) 10/13
  29. 29.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 1/12 (b) 1/18 (c) 1/11 (d) 2/11
  30. 30.A bag has 6 green, 4 blue and 6 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 3/8 (b) 5/8 (c) 1/3 (d) 3/5
  31. 31.A bag has 6 yellow, 5 green and 6 white balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 6/11 (b) 6/17 (c) 11/17 (d) 1/3
  32. 32.A fair dice is rolled once. What is the probability of getting a number less than 3? (a) 1/6 (b) 1/3 (c) 1/2 (d) 2/3
  33. 33.A bag has 4 white, 5 blue and 8 red balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 12/17 (c) 5/17 (d) 13/17
  34. 34.A bag has 9 green, 3 red and 5 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/3 (b) 13/17 (c) 5/17 (d) 12/17
  35. 35.A bag has 6 yellow, 7 white and 6 red balls. One ball is taken out without looking. What is the probability that it is not white? (a) 7/19 (b) 1/3 (c) 12/19 (d) 13/19
  36. 36.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 1/6 (b) 5/36 (c) 5/11 (d) 1/11
  37. 37.A bag has 5 white, 5 green and 4 red balls. One ball is taken out without looking. What is the probability that it is not white? (a) 9/14 (b) 5/7 (c) 1/3 (d) 5/14
  38. 38.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 7/8 (c) 1/7 (d) 1/8
  39. 39.A bag has 3 green, 3 white and 9 red balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/5 (b) 4/5 (c) 1/3 (d) 1/4
  40. 40.A bag has 9 red, 6 green and 8 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 15/23 (b) 8/23 (c) 16/23 (d) 1/3

Answer key

  1. 10/13
  2. 3/4
  3. 1/2
  4. 1/2
  5. 1/36
  6. 1/3
  7. 1/18
  8. 2/3
  9. 6/17
  10. 1/2
  11. 3/8
  12. 9/17
  13. 1/12
  14. 9/11
  15. 1/9
  16. 1/4
  17. 1/12
  18. 11/19
  19. 7/9
  20. 2/3
  21. 3/4
  22. 5/6
  23. 1/2
  24. 1/2
  25. 9/23
  26. 1/4
  27. 1/6
  28. 9/13
  29. 1/18
  30. 3/8
  31. 6/17
  32. 1/3
  33. 12/17
  34. 12/17
  35. 12/19
  36. 5/36
  37. 9/14
  38. 1/8
  39. 1/5
  40. 15/23

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