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Probability Worksheet for Class 8 Maths Olympiad

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

Answer key

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

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