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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 107 · 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.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 3/8 (b) 3/4 (c) 1/8 (d) 1/4
  2. 2.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 1/11 (b) 2/11 (c) 1/12 (d) 1/18
  3. 3.A bag has 7 green, 2 white and 4 blue balls. One ball is taken out without looking. What is the probability that it is not green? (a) 1/3 (b) 6/13 (c) 7/13 (d) 6/7
  4. 4.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/12 (b) 1/11 (c) 1/36 (d) 1/18
  5. 5.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/7 (b) 1/4 (c) 1/8 (d) 7/8
  6. 6.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/2 (b) 1/3 (c) 3/4 (d) 1/4
  7. 7.A bag has 4 white, 9 blue and 7 red balls. One ball is taken out without looking. What is the probability that it is blue? (a) 9/11 (b) 9/20 (c) 1/3 (d) 11/20
  8. 8.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 4/11 (b) 1/9 (c) 1/11 (d) 5/36
  9. 9.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/2 (b) 1/3 (c) 1/6 (d) 2/3
  10. 10.A bag has 5 white, 8 red and 2 blue balls. One ball is taken out without looking. What is the probability that it is not white? (a) 11/15 (b) 1/15 (c) 1/3 (d) 2/3
  11. 11.A bag has 5 red, 5 blue and 7 yellow balls. One ball is taken out without looking. What is the probability that it is not red? (a) 12/17 (b) 5/17 (c) 1/3 (d) 13/17
  12. 12.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
  13. 13.A bag has 7 yellow, 8 blue and 9 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 5/8 (b) 3/8 (c) 1/3 (d) 2/3
  14. 14.A bag has 2 yellow, 6 white and 2 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/4 (b) 4/5 (c) 1/3 (d) 1/5
  15. 15.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 3/11 (b) 1/11 (c) 1/12 (d) 1/9
  16. 16.A bag has 2 white, 3 blue and 3 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 3/8 (c) 5/8 (d) 3/5
  17. 17.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 7/36 (b) 6/11 (c) 1/6 (d) 1/11
  18. 18.Three coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 3/5 (c) 5/8 (d) 3/8
  19. 19.A bag has 5 green, 4 blue and 3 red balls. One ball is taken out without looking. What is the probability that it is not green? (a) 5/12 (b) 2/3 (c) 1/3 (d) 7/12
  20. 20.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 1/2 (c) 3/4 (d) 1/3
  21. 21.Two coins are tossed together. What is the probability of getting exactly one head? (a) 2/3 (b) 1/3 (c) 1/4 (d) 1/2
  22. 22.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 2/3 (b) 1/3 (c) 1/2 (d) 1/6
  23. 23.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/11 (b) 1/36 (c) 1/12 (d) 1/18
  24. 24.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/8 (b) 7/8 (c) 3/8 (d) 1/4
  25. 25.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/2 (b) 1/3 (c) 2/3 (d) 1/4
  26. 26.A bag has 2 green, 9 yellow and 6 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 15/17 (b) 2/17 (c) 2/15 (d) 1/3
  27. 27.A fair dice is rolled once. What is the probability of getting a number greater than 4? (a) 2/3 (b) 1/6 (c) 1/2 (d) 1/3
  28. 28.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
  29. 29.A bag has 2 yellow, 5 blue and 6 red balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/3 (b) 12/13 (c) 2/13 (d) 11/13
  30. 30.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/6 (b) 1/3 (c) 1/2 (d) 2/3
  31. 31.A bag has 4 red, 8 white and 9 blue balls. One ball is taken out without looking. What is the probability that it is red? (a) 1/3 (b) 17/21 (c) 4/17 (d) 4/21
  32. 32.A bag has 9 yellow, 2 green and 5 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 5/8 (b) 1/3 (c) 9/16 (d) 7/16
  33. 33.A bag has 3 blue, 3 red and 4 yellow balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 3/5 (b) 7/10 (c) 1/3 (d) 2/5
  34. 34.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/2 (b) 2/3 (c) 1/3 (d) 1/6
  35. 35.A bag has 8 green, 3 blue and 7 yellow balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/3 (b) 7/18 (c) 2/3 (d) 11/18
  36. 36.A fair dice is rolled once. What is the probability of getting a number less than 3? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
  37. 37.A bag has 7 red, 3 blue and 5 white balls. One ball is taken out without looking. What is the probability that it is red? (a) 7/15 (b) 1/3 (c) 7/8 (d) 8/15
  38. 38.A bag has 6 blue, 6 green and 2 white balls. One ball is taken out without looking. What is the probability that it is blue? (a) 3/4 (b) 4/7 (c) 3/7 (d) 1/3
  39. 39.A bag has 2 red, 5 blue and 2 yellow balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 4/9 (b) 1/3 (c) 4/5 (d) 5/9
  40. 40.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

Answer key

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

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