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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 966 · 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 fair dice is rolled once. What is the probability of getting a prime number? (a) 2/3 (b) 1/2 (c) 1/6 (d) 1/3
  2. 2.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 5/36 (b) 1/11 (c) 1/6 (d) 5/11
  3. 3.A bag has 5 red, 5 green and 9 yellow balls. One ball is taken out without looking. What is the probability that it is red? (a) 14/19 (b) 5/14 (c) 1/3 (d) 5/19
  4. 4.A fair dice is rolled once. What is the probability of getting a number less than 4? (a) 1/3 (b) 1/2 (c) 2/3 (d) 1/6
  5. 5.Three coins are tossed together. What is the probability of getting exactly one head? (a) 3/8 (b) 1/4 (c) 3/5 (d) 5/8
  6. 6.A bag has 4 blue, 7 green and 4 yellow balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 4/5 (b) 11/15 (c) 1/3 (d) 4/15
  7. 7.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 1/12 (b) 2/11 (c) 1/18 (d) 1/11
  8. 8.A bag has 8 green, 6 white and 8 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 4/7 (b) 4/11 (c) 1/3 (d) 7/11
  9. 9.A bag has 6 yellow, 5 white and 9 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 11/20 (b) 9/11 (c) 9/20 (d) 1/3
  10. 10.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
  11. 11.A bag has 6 blue, 3 white and 6 yellow balls. One ball is taken out without looking. What is the probability that it is white? (a) 4/5 (b) 1/3 (c) 1/5 (d) 1/4
  12. 12.A bag has 4 green, 2 yellow and 5 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 4/11 (b) 1/3 (c) 7/11 (d) 4/7
  13. 13.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/3 (b) 1/6 (c) 2/3 (d) 1/2
  14. 14.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 2/3 (b) 5/6 (c) 1/3 (d) 1/4
  15. 15.A bag has 5 red, 7 green and 4 yellow balls. One ball is taken out without looking. What is the probability that it is green? (a) 9/16 (b) 7/16 (c) 1/3 (d) 7/9
  16. 16.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
  17. 17.A bag has 4 blue, 4 red and 8 yellow balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 1/4 (c) 3/4 (d) 13/16
  18. 18.A bag has 3 blue, 4 white and 6 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 6/7 (b) 1/3 (c) 6/13 (d) 7/13
  19. 19.A bag has 8 yellow, 7 green and 2 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 8/9 (b) 1/3 (c) 9/17 (d) 8/17
  20. 20.A bag has 3 blue, 8 green and 6 yellow balls. One ball is taken out without looking. What is the probability that it is not green? (a) 9/17 (b) 10/17 (c) 8/17 (d) 1/3
  21. 21.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 6/11 (b) 1/11 (c) 1/6 (d) 7/36
  22. 22.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 1/11 (b) 5/36 (c) 1/9 (d) 4/11
  23. 23.A bag has 5 red, 4 yellow and 5 blue balls. One ball is taken out without looking. What is the probability that it is red? (a) 5/9 (b) 9/14 (c) 5/14 (d) 1/3
  24. 24.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
  25. 25.A bag has 9 green, 3 yellow and 6 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 1/2 (c) 1/18 (d) 5/9
  26. 26.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 1/7 (c) 7/8 (d) 1/8
  27. 27.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 1/11 (b) 5/36 (c) 4/11 (d) 1/9
  28. 28.A bag has 4 blue, 7 red and 8 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 8/11 (b) 1/3 (c) 8/19 (d) 11/19
  29. 29.A bag has 9 green, 9 red and 4 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 13/22 (b) 1/3 (c) 9/22 (d) 9/13
  30. 30.A bag has 9 white, 2 blue and 3 red balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/3 (b) 5/14 (c) 9/14 (d) 5/9
  31. 31.A fair dice is rolled once. What is the probability of getting an even number? (a) 2/3 (b) 1/3 (c) 1/6 (d) 1/2
  32. 32.A fair dice is rolled once. What is the probability of getting a number less than 2? (a) 1/6 (b) 1/3 (c) 1/5 (d) 5/6
  33. 33.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 1/6 (b) 5/36 (c) 5/11 (d) 1/11
  34. 34.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
  35. 35.Three coins are tossed together. What is the probability of getting at least one head? (a) 3/8 (b) 1/8 (c) 7/8 (d) 1/4
  36. 36.A bag has 6 yellow, 4 blue and 5 green balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/3 (b) 2/3 (c) 3/5 (d) 2/5
  37. 37.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/4 (b) 1/3 (c) 1/2 (d) 3/4
  38. 38.A bag has 4 blue, 3 red and 9 yellow balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 3/4 (b) 13/16 (c) 1/4 (d) 1/3
  39. 39.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/11 (b) 1/12 (c) 3/11 (d) 1/9
  40. 40.A bag has 9 blue, 4 red and 9 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 9/22 (b) 1/3 (c) 9/13 (d) 13/22

Answer key

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

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