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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 406 · 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.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 3/11 (b) 1/12 (c) 1/9 (d) 1/11
  2. 2.A bag has 8 blue, 4 green and 9 white balls. One ball is taken out without looking. What is the probability that it is not green? (a) 4/21 (b) 1/3 (c) 6/7 (d) 17/21
  3. 3.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/9 (b) 3/11 (c) 1/12 (d) 1/11
  4. 4.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/6 (b) 2/3 (c) 1/2 (d) 1/3
  5. 5.A bag has 2 yellow, 2 blue and 4 red balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 1/4 (c) 7/8 (d) 3/4
  6. 6.A bag has 8 red, 4 green and 5 blue balls. One ball is taken out without looking. What is the probability that it is not red? (a) 8/17 (b) 9/17 (c) 10/17 (d) 1/3
  7. 7.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/6 (b) 1/3 (c) 1/2 (d) 2/3
  8. 8.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/2 (b) 3/4 (c) 1/3 (d) 1/4
  9. 9.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/36 (b) 1/18 (c) 1/12 (d) 1/11
  10. 10.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/8 (b) 1/4 (c) 3/8 (d) 3/4
  11. 11.Three coins are tossed together. What is the probability of getting exactly one head? (a) 5/8 (b) 3/5 (c) 1/4 (d) 3/8
  12. 12.Two coins are tossed together. What is the probability of getting at least one head? (a) 3/4 (b) 1/2 (c) 1/4 (d) 1/3
  13. 13.A bag has 6 red, 3 blue and 5 green balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 3/14 (b) 6/7 (c) 1/3 (d) 11/14
  14. 14.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/2 (b) 2/3 (c) 1/4 (d) 1/3
  15. 15.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/3 (b) 2/3 (c) 1/4 (d) 1/2
  16. 16.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 2/11 (b) 1/18 (c) 1/11 (d) 1/12
  17. 17.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 1/6 (b) 1/11 (c) 5/36 (d) 5/11
  18. 18.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 1/9 (b) 5/36 (c) 4/11 (d) 1/11
  19. 19.A bag has 5 red, 2 green and 2 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 2/9 (b) 1/3 (c) 2/7 (d) 7/9
  20. 20.A bag has 4 green, 5 white and 7 yellow balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 5/16 (c) 3/4 (d) 1/4
  21. 21.A bag has 4 yellow, 6 green and 4 red balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 5/7 (b) 11/14 (c) 2/7 (d) 1/3
  22. 22.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 1/7 (c) 1/8 (d) 7/8
  23. 23.A bag has 2 red, 3 yellow and 6 white balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 2/11 (c) 9/11 (d) 10/11
  24. 24.A bag has 3 blue, 5 red and 5 white balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 10/13 (c) 11/13 (d) 3/13
  25. 25.A bag has 4 white, 2 blue and 2 yellow balls. One ball is taken out without looking. What is the probability that it is white? (a) 5/8 (b) 1/2 (c) 1/3 (d) 1/8
  26. 26.A bag has 5 red, 2 white and 3 yellow balls. One ball is taken out without looking. What is the probability that it is red? (a) 3/5 (b) 1/3 (c) 1/10 (d) 1/2
  27. 27.A bag has 3 green, 9 blue and 3 red balls. One ball is taken out without looking. What is the probability that it is blue? (a) 2/5 (b) 1/3 (c) 3/5 (d) 2/3
  28. 28.A bag has 7 yellow, 9 blue and 9 red balls. One ball is taken out without looking. What is the probability that it is red? (a) 9/25 (b) 16/25 (c) 1/3 (d) 9/16
  29. 29.A bag has 9 white, 4 red and 6 green balls. One ball is taken out without looking. What is the probability that it is white? (a) 9/19 (b) 10/19 (c) 9/10 (d) 1/3
  30. 30.A bag has 6 green, 3 yellow and 2 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 6/11 (b) 5/11 (c) 7/11 (d) 1/3
  31. 31.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 1/11 (b) 6/11 (c) 7/36 (d) 1/6
  32. 32.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/11 (b) 5/11 (c) 5/36 (d) 1/6
  33. 33.A bag has 3 white, 4 red and 9 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 9/16 (b) 1/3 (c) 7/16 (d) 7/9
  34. 34.A bag has 6 blue, 7 green and 3 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 7/16 (b) 1/3 (c) 7/9 (d) 9/16
  35. 35.Three coins are tossed together. What is the probability of getting at least one head? (a) 3/8 (b) 7/8 (c) 1/8 (d) 1/4
  36. 36.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/3 (b) 2/3 (c) 1/6 (d) 1/2
  37. 37.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 5/36 (b) 1/11 (c) 1/9 (d) 4/11
  38. 38.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/18 (b) 1/36 (c) 1/11 (d) 1/12
  39. 39.A bag has 5 yellow, 3 white and 3 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 6/11 (b) 5/6 (c) 1/3 (d) 5/11
  40. 40.A bag has 8 yellow, 8 green and 4 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 3/5 (b) 1/3 (c) 2/5 (d) 2/3

Answer key

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

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