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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 326 · 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, 3 yellow and 9 red balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/2 (b) 2/3 (c) 7/18 (d) 1/3
  2. 2.Two coins are tossed together. What is the probability of getting exactly one head? (a) 2/3 (b) 1/4 (c) 1/3 (d) 1/2
  3. 3.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/2 (b) 1/3 (c) 1/6 (d) 2/3
  4. 4.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 6/11 (b) 7/36 (c) 1/6 (d) 1/11
  5. 5.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 7/8 (b) 1/8 (c) 1/4 (d) 1/7
  6. 6.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/3 (b) 2/3 (c) 1/4 (d) 5/6
  7. 7.Two coins are tossed together. What is the probability of getting at least one head? (a) 3/4 (b) 1/4 (c) 1/2 (d) 1/3
  8. 8.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/2 (b) 2/3 (c) 1/6 (d) 1/3
  9. 9.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
  10. 10.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/12 (b) 3/11 (c) 1/9 (d) 1/11
  11. 11.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/3 (b) 2/3 (c) 1/6 (d) 1/2
  12. 12.A bag has 8 yellow, 8 red and 6 green balls. One ball is taken out without looking. What is the probability that it is red? (a) 4/7 (b) 4/11 (c) 7/11 (d) 1/3
  13. 13.A bag has 8 white, 9 red and 2 green balls. One ball is taken out without looking. What is the probability that it is not white? (a) 12/19 (b) 1/3 (c) 11/19 (d) 8/19
  14. 14.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 4/11 (b) 1/11 (c) 1/9 (d) 5/36
  15. 15.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 5/36 (b) 1/6 (c) 1/11 (d) 5/11
  16. 16.A fair dice is rolled once. What is the probability of getting a number less than 3? (a) 1/3 (b) 2/3 (c) 1/2 (d) 1/6
  17. 17.A bag has 8 white, 5 green and 8 red balls. One ball is taken out without looking. What is the probability that it is white? (a) 13/21 (b) 1/3 (c) 8/21 (d) 8/13
  18. 18.A bag has 3 blue, 3 green and 3 yellow balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 7/9 (b) 1/3 (c) 1/9 (d) 2/3
  19. 19.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/3 (b) 1/2 (c) 1/4 (d) 3/4
  20. 20.A bag has 8 blue, 3 yellow and 2 green balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 11/13 (b) 1/3 (c) 10/13 (d) 3/13
  21. 21.Three coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 5/8 (c) 3/5 (d) 3/8
  22. 22.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 3/4 (b) 1/8 (c) 3/8 (d) 1/4
  23. 23.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
  24. 24.A bag has 8 blue, 2 yellow and 3 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 3/13 (b) 3/10 (c) 1/3 (d) 10/13
  25. 25.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/36 (b) 1/18 (c) 1/11 (d) 1/12
  26. 26.A bag has 3 yellow, 7 blue and 7 green balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 10/17 (c) 7/17 (d) 7/10
  27. 27.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/6 (b) 1/11 (c) 5/11 (d) 5/36
  28. 28.A bag has 6 yellow, 4 blue and 3 green balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/3 (b) 8/13 (c) 6/13 (d) 7/13
  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) 1/5 (d) 5/6
  30. 30.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 1/12 (b) 1/11 (c) 3/11 (d) 1/9
  31. 31.A bag has 7 green, 6 blue and 8 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 8/21 (b) 1/3 (c) 8/13 (d) 13/21
  32. 32.A bag has 3 blue, 6 white and 2 red balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/3 (b) 6/11 (c) 7/11 (d) 5/11
  33. 33.A bag has 3 yellow, 7 red and 9 green balls. One ball is taken out without looking. What is the probability that it is red? (a) 7/12 (b) 12/19 (c) 1/3 (d) 7/19
  34. 34.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/4 (b) 3/8 (c) 1/8 (d) 7/8
  35. 35.A fair dice is rolled once. What is the probability of getting a number greater than 4? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
  36. 36.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 1/18 (b) 2/11 (c) 1/12 (d) 1/11
  37. 37.A bag has 5 yellow, 6 white and 8 blue balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 5/19 (b) 15/19 (c) 14/19 (d) 1/3
  38. 38.A bag has 6 green, 4 white and 9 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/3 (b) 4/19 (c) 16/19 (d) 15/19
  39. 39.A bag has 2 red, 4 white and 9 green 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
  40. 40.A fair dice is rolled once. What is the probability of getting a number less than 5? (a) 5/6 (b) 2/3 (c) 1/3 (d) 1/4

Answer key

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

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