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Probability Worksheet for Class 8 Maths Olympiad

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

Answer key

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

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