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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 265 · 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 3 red, 9 yellow and 5 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 13/17 (b) 12/17 (c) 5/17 (d) 1/3
  2. 2.A bag has 9 yellow, 6 white and 2 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 15/17 (c) 2/17 (d) 2/15
  3. 3.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
  4. 4.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/2 (b) 3/4 (c) 1/3 (d) 1/4
  5. 5.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/2 (b) 1/6 (c) 2/3 (d) 1/3
  6. 6.A bag has 7 yellow, 6 blue and 3 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 9/16 (c) 7/16 (d) 7/9
  7. 7.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/12 (b) 3/11 (c) 1/11 (d) 1/9
  8. 8.A fair dice is rolled once. What is the probability of getting a prime number? (a) 2/3 (b) 1/6 (c) 1/3 (d) 1/2
  9. 9.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 4/11 (b) 1/9 (c) 5/36 (d) 1/11
  10. 10.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/18 (b) 1/12 (c) 1/36 (d) 1/11
  11. 11.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/8 (b) 3/4 (c) 1/4 (d) 3/8
  12. 12.Three coins are tossed together. What is the probability of getting exactly one head? (a) 3/5 (b) 5/8 (c) 3/8 (d) 1/4
  13. 13.Three coins are tossed together. What is the probability of getting at least one head? (a) 7/8 (b) 1/8 (c) 1/4 (d) 3/8
  14. 14.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/3 (b) 1/2 (c) 1/4 (d) 2/3
  15. 15.A bag has 8 blue, 3 red and 8 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 8/11 (b) 8/19 (c) 11/19 (d) 1/3
  16. 16.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 1/11 (b) 1/9 (c) 1/12 (d) 3/11
  17. 17.A bag has 3 white, 8 blue and 3 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/3 (b) 3/14 (c) 6/7 (d) 11/14
  18. 18.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
  19. 19.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
  20. 20.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
  21. 21.A bag has 4 white, 7 blue and 5 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 5/11 (c) 5/16 (d) 11/16
  22. 22.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/6 (b) 1/3 (c) 1/2 (d) 2/3
  23. 23.A bag has 8 green, 4 yellow and 3 red balls. One ball is taken out without looking. What is the probability that it is not green? (a) 7/8 (b) 7/15 (c) 8/15 (d) 1/3
  24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 1/11 (b) 1/12 (c) 2/11 (d) 1/18
  25. 25.A bag has 5 yellow, 8 green and 2 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 2/3 (c) 2/5 (d) 1/2
  26. 26.A bag has 4 green, 3 blue and 5 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/2 (b) 5/12 (c) 2/3 (d) 1/3
  27. 27.A bag has 3 red, 3 blue and 2 green balls. One ball is taken out without looking. What is the probability that it is red? (a) 3/8 (b) 5/8 (c) 1/3 (d) 3/5
  28. 28.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/4 (b) 1/2 (c) 3/4 (d) 1/3
  29. 29.A fair dice is rolled once. What is the probability of getting a number less than 2? (a) 1/3 (b) 1/6 (c) 5/6 (d) 1/5
  30. 30.A bag has 3 red, 4 blue and 3 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 3/10 (b) 1/3 (c) 4/5 (d) 7/10
  31. 31.A bag has 9 yellow, 9 blue and 2 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/9 (b) 1/3 (c) 9/10 (d) 1/10
  32. 32.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/4 (b) 1/3 (c) 5/6 (d) 2/3
  33. 33.A bag has 6 blue, 8 red and 4 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 7/9 (b) 2/7 (c) 1/3 (d) 2/9
  34. 34.A bag has 8 red, 7 blue and 2 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 2/17 (b) 2/15 (c) 15/17 (d) 1/3
  35. 35.A bag has 9 yellow, 6 blue and 6 red balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 13/21 (b) 4/7 (c) 1/3 (d) 3/7
  36. 36.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/4 (b) 1/2 (c) 1/3 (d) 2/3
  37. 37.A bag has 6 red, 7 green and 2 white balls. One ball is taken out without looking. What is the probability that it is not red? (a) 2/3 (b) 1/3 (c) 3/5 (d) 2/5
  38. 38.A bag has 8 yellow, 4 red and 4 green balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/4 (b) 13/16 (c) 1/3 (d) 3/4
  39. 39.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/12 (b) 2/11 (c) 1/11 (d) 1/18
  40. 40.A bag has 6 green, 2 red and 6 white balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 1/7 (c) 13/14 (d) 6/7

Answer key

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

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