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Probability Worksheet for Class 8 Maths Olympiad

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

Answer key

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

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