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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 392 · 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 prime number? (a) 1/6 (b) 1/2 (c) 1/3 (d) 2/3
  2. 2.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
  3. 3.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/18 (b) 1/11 (c) 1/36 (d) 1/12
  4. 4.A fair dice is rolled once. What is the probability of getting an even number? (a) 2/3 (b) 1/6 (c) 1/3 (d) 1/2
  5. 5.A fair dice is rolled once. What is the probability of getting a number less than 5? (a) 5/6 (b) 1/3 (c) 1/4 (d) 2/3
  6. 6.A bag has 4 red, 9 yellow and 7 green balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 11/20 (b) 1/3 (c) 9/20 (d) 9/11
  7. 7.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 6/11 (b) 1/11 (c) 7/36 (d) 1/6
  8. 8.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 3/11 (b) 1/12 (c) 1/11 (d) 1/9
  9. 9.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/3 (b) 5/6 (c) 2/3 (d) 1/4
  10. 10.A bag has 3 green, 4 red and 9 white balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 3/4 (c) 1/4 (d) 13/16
  11. 11.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/2 (b) 2/3 (c) 1/3 (d) 1/4
  12. 12.Three coins are tossed together. What is the probability of getting exactly one head? (a) 5/8 (b) 1/4 (c) 3/8 (d) 3/5
  13. 13.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/2 (b) 2/3 (c) 1/3 (d) 1/4
  14. 14.A bag has 4 blue, 3 red and 4 green balls. One ball is taken out without looking. What is the probability that it is blue? (a) 4/7 (b) 7/11 (c) 1/3 (d) 4/11
  15. 15.A fair dice is rolled once. What is the probability of getting an odd number? (a) 2/3 (b) 1/2 (c) 1/6 (d) 1/3
  16. 16.A bag has 3 white, 3 green and 5 yellow balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 7/11 (b) 5/11 (c) 6/11 (d) 1/3
  17. 17.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/8 (b) 1/4 (c) 7/8 (d) 3/8
  18. 18.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 2/3 (b) 1/6 (c) 1/3 (d) 1/2
  19. 19.A bag has 9 blue, 9 yellow and 7 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/3 (b) 19/25 (c) 7/25 (d) 18/25
  20. 20.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/12 (b) 1/11 (c) 2/11 (d) 1/18
  21. 21.A bag has 8 green, 7 blue and 3 red balls. One ball is taken out without looking. What is the probability that it is not green? (a) 11/18 (b) 5/9 (c) 1/3 (d) 4/9
  22. 22.A bag has 8 yellow, 6 red and 2 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/3 (b) 15/16 (c) 1/8 (d) 7/8
  23. 23.A fair dice is rolled once. What is the probability of getting a number greater than 2? (a) 5/6 (b) 1/4 (c) 2/3 (d) 1/3
  24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 1/9 (b) 1/11 (c) 5/36 (d) 4/11
  25. 25.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/3 (b) 3/4 (c) 1/2 (d) 1/4
  26. 26.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 1/11 (b) 1/18 (c) 1/12 (d) 2/11
  27. 27.A bag has 3 blue, 8 green and 8 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 11/19 (c) 8/11 (d) 8/19
  28. 28.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/11 (b) 1/18 (c) 1/36 (d) 1/12
  29. 29.A bag has 4 red, 5 white and 2 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 2/11 (c) 2/9 (d) 9/11
  30. 30.A bag has 3 green, 8 blue and 4 red balls. One ball is taken out without looking. What is the probability that it is not green? (a) 1/5 (b) 13/15 (c) 1/3 (d) 4/5
  31. 31.A bag has 2 red, 6 white and 9 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 8/17 (b) 8/9 (c) 1/3 (d) 9/17
  32. 32.A bag has 9 yellow, 8 green and 4 blue balls. One ball is taken out without looking. What is the probability that it is not green? (a) 8/21 (b) 1/3 (c) 13/21 (d) 2/3
  33. 33.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 7/8 (b) 1/4 (c) 1/7 (d) 1/8
  34. 34.A bag has 7 red, 5 yellow and 3 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/5 (b) 13/15 (c) 4/5 (d) 1/3
  35. 35.A bag has 8 green, 4 yellow and 2 red balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 5/7 (b) 2/7 (c) 11/14 (d) 1/3
  36. 36.A bag has 9 yellow, 9 white and 7 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 9/25 (b) 1/3 (c) 9/16 (d) 16/25
  37. 37.A bag has 9 green, 4 yellow and 3 white balls. One ball is taken out without looking. What is the probability that it is not green? (a) 7/16 (b) 9/16 (c) 7/9 (d) 1/3
  38. 38.A bag has 3 blue, 9 yellow and 8 red balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 17/20 (c) 9/10 (d) 3/20
  39. 39.A bag has 2 white, 3 green and 5 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 3/5 (b) 1/10 (c) 1/2 (d) 1/3
  40. 40.A bag has 8 white, 4 red and 8 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 2/5 (b) 3/5 (c) 1/3 (d) 13/20

Answer key

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

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