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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 105 · 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 blue, 9 red and 4 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 16/19 (b) 1/3 (c) 15/19 (d) 4/19
  2. 2.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 3/8 (b) 1/4 (c) 3/4 (d) 1/8
  3. 3.A bag has 7 yellow, 7 white and 6 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 7/10 (b) 3/7 (c) 3/10 (d) 1/3
  4. 4.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/12 (b) 1/36 (c) 1/11 (d) 1/18
  5. 5.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 5/6 (b) 1/3 (c) 2/3 (d) 1/4
  6. 6.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
  7. 7.A bag has 5 green, 3 red and 3 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 3/11 (b) 9/11 (c) 1/3 (d) 8/11
  8. 8.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 4/11 (b) 5/36 (c) 1/9 (d) 1/11
  9. 9.A fair dice is rolled once. What is the probability of getting a prime number? (a) 2/3 (b) 1/3 (c) 1/6 (d) 1/2
  10. 10.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/2 (b) 1/6 (c) 2/3 (d) 1/3
  11. 11.A fair dice is rolled once. What is the probability of getting a number less than 3? (a) 2/3 (b) 1/6 (c) 1/2 (d) 1/3
  12. 12.A bag has 9 green, 8 red and 7 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 3/8 (b) 5/8 (c) 1/3 (d) 3/5
  13. 13.A bag has 8 yellow, 7 blue and 6 red balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 2/3 (c) 1/2 (d) 8/21
  14. 14.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) 1/4 (d) 1/3
  15. 15.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/4 (b) 3/4 (c) 1/2 (d) 1/3
  16. 16.A fair dice is rolled once. What is the probability of getting a number less than 5? (a) 1/4 (b) 1/3 (c) 2/3 (d) 5/6
  17. 17.A fair dice is rolled once. What is the probability of getting a number greater than 2? (a) 2/3 (b) 1/4 (c) 5/6 (d) 1/3
  18. 18.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/2 (b) 2/3 (c) 1/6 (d) 1/3
  19. 19.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 1/9 (b) 5/36 (c) 1/11 (d) 4/11
  20. 20.A bag has 9 green, 3 white and 2 blue balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 9/14 (c) 5/7 (d) 5/14
  21. 21.A bag has 2 white, 6 green and 5 blue balls. One ball is taken out without looking. What is the probability that it is green? (a) 6/13 (b) 7/13 (c) 1/3 (d) 6/7
  22. 22.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 1/3 (c) 1/2 (d) 2/3
  23. 23.A bag has 5 green, 9 red and 4 yellow balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 2/9 (b) 5/6 (c) 1/3 (d) 7/9
  24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/11 (b) 1/6 (c) 5/36 (d) 5/11
  25. 25.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/18 (b) 1/36 (c) 1/11 (d) 1/12
  26. 26.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 3/11 (b) 1/11 (c) 1/12 (d) 1/9
  27. 27.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 1/12 (b) 3/11 (c) 1/9 (d) 1/11
  28. 28.A bag has 3 white, 2 red and 4 blue balls. One ball is taken out without looking. What is the probability that it is not white? (a) 2/3 (b) 7/9 (c) 1/3 (d) 1/9
  29. 29.A bag has 7 yellow, 2 green and 2 red balls. One ball is taken out without looking. What is the probability that it is not red? (a) 10/11 (b) 2/11 (c) 1/3 (d) 9/11
  30. 30.A bag has 6 yellow, 9 white and 8 red balls. One ball is taken out without looking. What is the probability that it is not red? (a) 8/23 (b) 15/23 (c) 1/3 (d) 16/23
  31. 31.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
  32. 32.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/6 (b) 1/2 (c) 2/3 (d) 1/3
  33. 33.A bag has 6 yellow, 6 white and 3 green balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 2/5 (b) 2/3 (c) 1/3 (d) 3/5
  34. 34.A fair dice is rolled once. What is the probability of getting a number less than 4? (a) 1/3 (b) 1/2 (c) 1/6 (d) 2/3
  35. 35.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/8 (b) 1/7 (c) 7/8 (d) 1/4
  36. 36.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 7/36 (b) 1/6 (c) 6/11 (d) 1/11
  37. 37.A bag has 9 blue, 8 yellow and 7 white balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 3/5 (c) 3/8 (d) 5/8
  38. 38.A bag has 5 white, 9 red and 2 blue balls. One ball is taken out without looking. What is the probability that it is white? (a) 11/16 (b) 1/3 (c) 5/16 (d) 5/11
  39. 39.A bag has 2 red, 8 yellow and 2 blue balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/2 (b) 2/3 (c) 5/12 (d) 1/3
  40. 40.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

Answer key

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

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