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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 351 · 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 fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/3 (b) 5/6 (c) 1/4 (d) 2/3
  2. 2.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 1/2 (c) 2/3 (d) 1/3
  3. 3.A bag has 3 yellow, 2 green and 4 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 5/9 (b) 4/9 (c) 4/5 (d) 1/3
  4. 4.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 3/4 (b) 1/4 (c) 1/2 (d) 1/3
  5. 5.A bag has 8 green, 2 red and 2 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/6 (b) 1/3 (c) 5/6 (d) 11/12
  6. 6.A bag has 5 green, 2 yellow and 7 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/7 (b) 1/3 (c) 6/7 (d) 1/6
  7. 7.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 2/3 (b) 1/2 (c) 1/6 (d) 1/3
  8. 8.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/2 (b) 2/3 (c) 1/6 (d) 1/3
  9. 9.Three coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 3/8 (c) 3/5 (d) 5/8
  10. 10.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 5/36 (b) 1/9 (c) 4/11 (d) 1/11
  11. 11.A bag has 7 blue, 9 yellow and 4 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/5 (b) 17/20 (c) 4/5 (d) 1/3
  12. 12.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/3 (b) 2/3 (c) 1/2 (d) 1/6
  13. 13.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/3 (b) 1/6 (c) 2/3 (d) 1/2
  14. 14.A bag has 8 green, 4 yellow and 7 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 4/15 (b) 15/19 (c) 1/3 (d) 4/19
  15. 15.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 1/6 (b) 6/11 (c) 1/11 (d) 7/36
  16. 16.A bag has 9 yellow, 6 red and 7 white balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 9/22 (b) 9/13 (c) 1/3 (d) 13/22
  17. 17.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 3/11 (b) 1/11 (c) 1/9 (d) 1/12
  18. 18.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/3 (b) 1/2 (c) 2/3 (d) 1/4
  19. 19.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/3 (b) 1/4 (c) 3/4 (d) 1/2
  20. 20.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/4 (b) 1/8 (c) 3/8 (d) 3/4
  21. 21.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/11 (b) 1/18 (c) 1/12 (d) 1/36
  22. 22.A bag has 6 yellow, 4 red and 2 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/6 (b) 1/3 (c) 11/12 (d) 5/6
  23. 23.A bag has 4 red, 9 blue and 2 green balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 4/15 (c) 11/15 (d) 4/5
  24. 24.A bag has 2 green, 4 yellow and 3 blue balls. One ball is taken out without looking. What is the probability that it is not green? (a) 2/9 (b) 1/3 (c) 7/9 (d) 8/9
  25. 25.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 5/11 (b) 5/36 (c) 1/6 (d) 1/11
  26. 26.A bag has 4 yellow, 7 blue and 8 green balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 7/19 (b) 13/19 (c) 1/3 (d) 12/19
  27. 27.A fair dice is rolled once. What is the probability of getting a number less than 2? (a) 1/6 (b) 1/3 (c) 1/5 (d) 5/6
  28. 28.A bag has 6 blue, 7 red and 2 green balls. One ball is taken out without looking. What is the probability that it is not red? (a) 3/5 (b) 7/15 (c) 8/15 (d) 1/3
  29. 29.A bag has 6 green, 7 yellow and 9 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 7/11 (b) 9/22 (c) 13/22 (d) 1/3
  30. 30.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/18 (b) 1/36 (c) 1/12 (d) 1/11
  31. 31.A bag has 7 white, 3 blue and 8 green balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/6 (b) 8/9 (c) 1/3 (d) 5/6
  32. 32.A bag has 4 red, 8 blue and 3 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/4 (b) 1/5 (c) 1/3 (d) 4/5
  33. 33.A fair dice is rolled once. What is the probability of getting a number less than 5? (a) 1/4 (b) 2/3 (c) 1/3 (d) 5/6
  34. 34.A bag has 8 blue, 6 white and 2 red balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 9/16 (b) 1/2 (c) 1/16 (d) 1/3
  35. 35.A bag has 6 green, 8 yellow and 6 red balls. One ball is taken out without looking. What is the probability that it is red? (a) 3/7 (b) 1/3 (c) 3/10 (d) 7/10
  36. 36.A fair dice is rolled once. What is the probability of getting a number greater than 2? (a) 1/3 (b) 2/3 (c) 1/4 (d) 5/6
  37. 37.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 5/36 (b) 4/11 (c) 1/9 (d) 1/11
  38. 38.A bag has 9 red, 3 green and 5 blue balls. One ball is taken out without looking. What is the probability that it is not red? (a) 8/9 (b) 8/17 (c) 1/3 (d) 9/17
  39. 39.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 1/12 (b) 1/11 (c) 2/11 (d) 1/18
  40. 40.A bag has 9 white, 5 yellow and 8 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 4/11 (b) 4/7 (c) 7/11 (d) 1/3

Answer key

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

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