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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 310 · 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 6 yellow, 4 red and 8 blue balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 5/6 (c) 7/9 (d) 2/9
  2. 2.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
  3. 3.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/18 (b) 1/11 (c) 1/36 (d) 1/12
  4. 4.A bag has 5 red, 9 blue and 4 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 1/18 (c) 5/9 (d) 1/2
  5. 5.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/4 (b) 2/3 (c) 1/3 (d) 1/2
  6. 6.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/2 (b) 1/6 (c) 2/3 (d) 1/3
  7. 7.A bag has 2 red, 6 white and 9 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 6/17 (b) 11/17 (c) 12/17 (d) 1/3
  8. 8.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/3 (b) 2/3 (c) 1/4 (d) 5/6
  9. 9.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/2 (b) 1/4 (c) 3/4 (d) 1/3
  10. 10.Three coins are tossed together. What is the probability of getting exactly one head? (a) 3/8 (b) 5/8 (c) 1/4 (d) 3/5
  11. 11.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
  12. 12.A bag has 2 blue, 8 yellow and 9 green balls. One ball is taken out without looking. What is the probability that it is blue? (a) 2/19 (b) 17/19 (c) 2/17 (d) 1/3
  13. 13.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/8 (b) 1/4 (c) 1/7 (d) 7/8
  14. 14.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
  15. 15.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/2 (b) 2/3 (c) 1/3 (d) 1/6
  16. 16.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/8 (b) 3/8 (c) 1/4 (d) 7/8
  17. 17.A bag has 2 red, 2 blue and 2 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 5/6 (b) 2/3 (c) 1/6 (d) 1/3
  18. 18.Two coins are tossed together. What is the probability of getting exactly one head? (a) 2/3 (b) 1/3 (c) 1/2 (d) 1/4
  19. 19.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 5/36 (b) 4/11 (c) 1/9 (d) 1/11
  20. 20.A bag has 4 green, 7 white and 3 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 3/14 (b) 1/3 (c) 11/14 (d) 3/11
  21. 21.A bag has 2 blue, 5 green and 4 white balls. One ball is taken out without looking. What is the probability that it is blue? (a) 2/9 (b) 9/11 (c) 1/3 (d) 2/11
  22. 22.A bag has 3 blue, 2 red and 8 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 8/13 (b) 9/13 (c) 5/13 (d) 1/3
  23. 23.A bag has 8 white, 3 green and 3 blue balls. One ball is taken out without looking. What is the probability that it is not white? (a) 3/7 (b) 1/3 (c) 3/4 (d) 4/7
  24. 24.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/2 (b) 3/4 (c) 1/4 (d) 1/3
  25. 25.A fair dice is rolled once. What is the probability of getting a number less than 4? (a) 1/6 (b) 2/3 (c) 1/2 (d) 1/3
  26. 26.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 1/6 (b) 1/11 (c) 5/11 (d) 5/36
  27. 27.A bag has 3 blue, 9 red and 4 green balls. One ball is taken out without looking. What is the probability that it is blue? (a) 3/13 (b) 13/16 (c) 1/3 (d) 3/16
  28. 28.A bag has 7 red, 8 yellow and 5 green balls. One ball is taken out without looking. What is the probability that it is red? (a) 7/20 (b) 1/3 (c) 13/20 (d) 7/13
  29. 29.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/3 (b) 2/3 (c) 1/2 (d) 1/6
  30. 30.A bag has 5 green, 5 red and 7 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 10/17 (b) 1/3 (c) 7/17 (d) 7/10
  31. 31.A bag has 2 green, 3 red and 6 blue balls. One ball is taken out without looking. What is the probability that it is green? (a) 2/11 (b) 1/3 (c) 9/11 (d) 2/9
  32. 32.A fair dice is rolled once. What is the probability of getting a number greater than 2? (a) 5/6 (b) 2/3 (c) 1/3 (d) 1/4
  33. 33.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
  34. 34.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 5/11 (b) 1/11 (c) 1/6 (d) 5/36
  35. 35.A bag has 9 yellow, 9 blue and 6 white balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 2/3 (b) 5/8 (c) 3/8 (d) 1/3
  36. 36.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 3/4 (b) 3/8 (c) 1/8 (d) 1/4
  37. 37.A bag has 2 white, 3 green and 4 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 4/5 (c) 5/9 (d) 4/9
  38. 38.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 5/36 (b) 1/9 (c) 1/11 (d) 4/11
  39. 39.A bag has 3 green, 5 blue and 6 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 3/11 (b) 11/14 (c) 3/14 (d) 1/3
  40. 40.A fair dice is rolled once. What is the probability of getting a number greater than 3? (a) 1/6 (b) 2/3 (c) 1/3 (d) 1/2

Answer key

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

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