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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 99 · 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 dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/11 (b) 1/9 (c) 1/12 (d) 3/11
  2. 2.A bag has 4 blue, 4 red and 2 white balls. One ball is taken out without looking. What is the probability that it is blue? (a) 2/5 (b) 1/3 (c) 3/5 (d) 2/3
  3. 3.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 1/6 (b) 5/11 (c) 5/36 (d) 1/11
  4. 4.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/2 (b) 1/3 (c) 1/4 (d) 2/3
  5. 5.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/11 (b) 1/6 (c) 5/11 (d) 5/36
  6. 6.A bag has 4 red, 6 yellow and 8 blue balls. One ball is taken out without looking. What is the probability that it is not red? (a) 7/9 (b) 1/3 (c) 2/9 (d) 5/6
  7. 7.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/36 (b) 1/11 (c) 1/12 (d) 1/18
  8. 8.A bag has 3 yellow, 8 blue and 8 green balls. One ball is taken out without looking. What is the probability that it is blue? (a) 11/19 (b) 1/3 (c) 8/11 (d) 8/19
  9. 9.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
  10. 10.A bag has 7 red, 2 white and 2 green balls. One ball is taken out without looking. What is the probability that it is not white? (a) 10/11 (b) 1/3 (c) 9/11 (d) 2/11
  11. 11.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
  12. 12.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/4 (b) 1/3 (c) 2/3 (d) 5/6
  13. 13.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 3/4 (b) 1/3 (c) 1/2 (d) 1/4
  14. 14.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/3 (b) 1/4 (c) 1/2 (d) 3/4
  15. 15.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 1/2 (c) 2/3 (d) 1/3
  16. 16.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/7 (b) 1/4 (c) 7/8 (d) 1/8
  17. 17.Three coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 3/5 (c) 3/8 (d) 5/8
  18. 18.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
  19. 19.A bag has 2 yellow, 4 green and 6 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 2/3 (b) 1/3 (c) 5/12 (d) 1/2
  20. 20.A bag has 7 yellow, 2 blue and 7 green balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 7/16 (b) 7/9 (c) 9/16 (d) 1/3
  21. 21.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
  22. 22.A bag has 7 green, 6 yellow and 6 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 7/19 (b) 7/12 (c) 1/3 (d) 12/19
  23. 23.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
  24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 3/11 (b) 1/12 (c) 1/11 (d) 1/9
  25. 25.A bag has 2 blue, 8 red and 2 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/5 (b) 1/3 (c) 5/6 (d) 1/6
  26. 26.A bag has 2 white, 2 green and 7 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 9/11 (b) 1/3 (c) 10/11 (d) 2/11
  27. 27.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 5/36 (b) 1/9 (c) 1/11 (d) 4/11
  28. 28.A bag has 6 yellow, 6 white and 2 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 6/7 (b) 1/7 (c) 1/3 (d) 13/14
  29. 29.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 4/11 (b) 1/9 (c) 1/11 (d) 5/36
  30. 30.A bag has 7 white, 8 green and 5 yellow balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/4 (b) 4/5 (c) 1/3 (d) 3/4
  31. 31.A bag has 9 yellow, 7 white and 5 red balls. One ball is taken out without looking. What is the probability that it is not red? (a) 17/21 (b) 5/21 (c) 1/3 (d) 16/21
  32. 32.A fair dice is rolled once. What is the probability of getting a number less than 2? (a) 1/5 (b) 1/6 (c) 1/3 (d) 5/6
  33. 33.A bag has 2 white, 7 blue and 3 green balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/3 (b) 1/6 (c) 5/6 (d) 1/5
  34. 34.Three coins are tossed together. What is the probability of getting at least one head? (a) 7/8 (b) 3/8 (c) 1/8 (d) 1/4
  35. 35.A bag has 5 blue, 2 white and 8 yellow balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 2/3 (b) 11/15 (c) 1/15 (d) 1/3
  36. 36.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/18 (b) 1/12 (c) 2/11 (d) 1/11
  37. 37.A bag has 2 blue, 7 green and 6 white balls. One ball is taken out without looking. What is the probability that it is not green? (a) 1/3 (b) 7/15 (c) 8/15 (d) 3/5
  38. 38.A bag has 7 green, 8 yellow and 9 blue balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/3 (b) 1/24 (c) 17/24 (d) 2/3
  39. 39.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 2/3 (b) 1/3 (c) 1/6 (d) 1/2
  40. 40.A bag has 3 blue, 9 green and 3 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/5 (b) 4/5 (c) 1/3 (d) 1/4

Answer key

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

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