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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 68 · 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 number greater than 3? (a) 1/3 (b) 1/2 (c) 2/3 (d) 1/6
  2. 2.A bag has 9 red, 3 green and 4 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 5/16 (b) 1/3 (c) 1/4 (d) 3/4
  3. 3.A bag has 3 blue, 8 white and 9 green balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/3 (b) 2/5 (c) 2/3 (d) 3/5
  4. 4.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 7/8 (c) 1/8 (d) 1/7
  5. 5.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/11 (b) 2/11 (c) 1/18 (d) 1/12
  6. 6.A bag has 2 blue, 7 yellow and 2 red balls. One ball is taken out without looking. What is the probability that it is red? (a) 9/11 (b) 2/11 (c) 1/3 (d) 2/9
  7. 7.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 1/11 (b) 1/9 (c) 3/11 (d) 1/12
  8. 8.A bag has 9 yellow, 2 red and 3 green balls. One ball is taken out without looking. What is the probability that it is not red? (a) 13/14 (b) 6/7 (c) 1/3 (d) 1/7
  9. 9.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/2 (b) 2/3 (c) 1/3 (d) 1/6
  10. 10.A bag has 7 red, 5 white and 4 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 11/16 (b) 1/3 (c) 5/16 (d) 3/4
  11. 11.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
  12. 12.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/2 (b) 1/6 (c) 2/3 (d) 1/3
  13. 13.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/4 (b) 3/8 (c) 7/8 (d) 1/8
  14. 14.A bag has 4 green, 6 white and 5 red balls. One ball is taken out without looking. What is the probability that it is not green? (a) 4/5 (b) 11/15 (c) 4/15 (d) 1/3
  15. 15.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/2 (b) 3/4 (c) 1/4 (d) 1/3
  16. 16.Three coins are tossed together. What is the probability of getting exactly one head? (a) 5/8 (b) 3/5 (c) 1/4 (d) 3/8
  17. 17.A bag has 2 blue, 8 red and 5 white balls. One ball is taken out without looking. What is the probability that it is not red? (a) 8/15 (b) 1/3 (c) 7/8 (d) 7/15
  18. 18.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/8 (b) 3/4 (c) 3/8 (d) 1/4
  19. 19.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/2 (b) 1/3 (c) 2/3 (d) 1/6
  20. 20.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/4 (b) 2/3 (c) 5/6 (d) 1/3
  21. 21.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 7/36 (b) 1/6 (c) 6/11 (d) 1/11
  22. 22.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
  23. 23.A bag has 3 white, 3 red and 6 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/4 (b) 5/6 (c) 3/4 (d) 1/3
  24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/12 (b) 1/36 (c) 1/11 (d) 1/18
  25. 25.A bag has 7 red, 5 white and 9 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 17/21 (b) 5/21 (c) 16/21 (d) 1/3
  26. 26.A bag has 3 white, 6 red and 4 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 4/13 (c) 4/9 (d) 9/13
  27. 27.A fair dice is rolled once. What is the probability of getting a number greater than 4? (a) 2/3 (b) 1/2 (c) 1/6 (d) 1/3
  28. 28.A bag has 6 yellow, 3 green and 3 red balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/4 (b) 5/6 (c) 1/3 (d) 3/4
  29. 29.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 1/3 (c) 1/2 (d) 2/3
  30. 30.A bag has 9 yellow, 5 blue and 9 red balls. One ball is taken out without looking. What is the probability that it is blue? (a) 5/18 (b) 18/23 (c) 5/23 (d) 1/3
  31. 31.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 1/9 (b) 5/36 (c) 4/11 (d) 1/11
  32. 32.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/6 (b) 5/36 (c) 1/11 (d) 5/11
  33. 33.A fair dice is rolled once. What is the probability of getting a number less than 3? (a) 1/6 (b) 1/2 (c) 2/3 (d) 1/3
  34. 34.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 1/11 (b) 4/11 (c) 1/9 (d) 5/36
  35. 35.A bag has 7 blue, 7 yellow and 3 green balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 10/17 (c) 7/10 (d) 7/17
  36. 36.A bag has 2 red, 6 green and 8 yellow balls. One ball is taken out without looking. What is the probability that it is red? (a) 7/8 (b) 1/7 (c) 1/8 (d) 1/3
  37. 37.A bag has 7 green, 3 blue and 7 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 7/10 (b) 1/3 (c) 7/17 (d) 10/17
  38. 38.A bag has 4 white, 7 yellow and 6 green balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 7/10 (b) 10/17 (c) 7/17 (d) 1/3
  39. 39.A bag has 5 red, 3 green and 3 blue balls. One ball is taken out without looking. What is the probability that it is not red? (a) 6/11 (b) 5/11 (c) 7/11 (d) 1/3
  40. 40.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 1/6 (b) 5/11 (c) 1/11 (d) 5/36

Answer key

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

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