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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 50 · 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 9? (a) 4/11 (b) 1/9 (c) 5/36 (d) 1/11
  2. 2.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 5/6 (b) 2/3 (c) 1/3 (d) 1/4
  3. 3.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 2/3 (b) 1/6 (c) 1/3 (d) 1/2
  4. 4.Three coins are tossed together. What is the probability of getting exactly one head? (a) 3/5 (b) 5/8 (c) 1/4 (d) 3/8
  5. 5.A fair dice is rolled once. What is the probability of getting a number less than 5? (a) 5/6 (b) 1/4 (c) 1/3 (d) 2/3
  6. 6.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 1/9 (b) 1/12 (c) 1/11 (d) 3/11
  7. 7.A bag has 7 red, 4 green and 5 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/4 (b) 3/4 (c) 5/16 (d) 1/3
  8. 8.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) 1/4 (d) 3/8
  9. 9.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/3 (b) 1/2 (c) 1/4 (d) 2/3
  10. 10.A bag has 6 blue, 6 green and 2 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 3/4 (b) 4/7 (c) 1/3 (d) 3/7
  11. 11.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/18 (b) 1/12 (c) 1/11 (d) 1/36
  12. 12.A bag has 3 white, 4 blue and 8 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 11/15 (b) 4/11 (c) 1/3 (d) 4/15
  13. 13.A bag has 3 white, 9 blue and 3 yellow balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/3 (b) 4/5 (c) 1/5 (d) 1/4
  14. 14.A bag has 5 green, 7 blue and 9 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 8/21 (b) 2/3 (c) 1/3 (d) 1/2
  15. 15.A bag has 3 white, 3 red and 8 yellow balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/3 (b) 3/4 (c) 4/7 (d) 3/7
  16. 16.A bag has 3 red, 8 blue and 2 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 2/11 (b) 11/13 (c) 2/13 (d) 1/3
  17. 17.A bag has 2 white, 3 green and 3 blue balls. One ball is taken out without looking. What is the probability that it is not green? (a) 3/8 (b) 5/8 (c) 1/3 (d) 3/4
  18. 18.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/9 (b) 3/11 (c) 1/11 (d) 1/12
  19. 19.A bag has 5 yellow, 8 red and 2 green balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/3 (b) 11/15 (c) 2/3 (d) 1/15
  20. 20.A fair dice is rolled once. What is the probability of getting an odd number? (a) 2/3 (b) 1/3 (c) 1/6 (d) 1/2
  21. 21.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/4 (b) 1/2 (c) 1/3 (d) 3/4
  22. 22.A fair dice is rolled once. What is the probability of getting an even number? (a) 2/3 (b) 1/2 (c) 1/3 (d) 1/6
  23. 23.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
  24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 1/11 (b) 1/9 (c) 4/11 (d) 5/36
  25. 25.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/7 (b) 1/8 (c) 7/8 (d) 1/4
  26. 26.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/36 (b) 1/12 (c) 1/18 (d) 1/11
  27. 27.A bag has 2 red, 7 green and 2 blue balls. One ball is taken out without looking. What is the probability that it is not red? (a) 9/11 (b) 10/11 (c) 1/3 (d) 2/11
  28. 28.A bag has 9 green, 8 white and 4 red balls. One ball is taken out without looking. What is the probability that it is red? (a) 17/21 (b) 4/17 (c) 1/3 (d) 4/21
  29. 29.A fair dice is rolled once. What is the probability of getting a prime number? (a) 2/3 (b) 1/6 (c) 1/3 (d) 1/2
  30. 30.A fair dice is rolled once. What is the probability of getting a number less than 4? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
  31. 31.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/8 (b) 3/8 (c) 7/8 (d) 1/4
  32. 32.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 2/3 (b) 1/2 (c) 1/4 (d) 1/3
  33. 33.A bag has 3 green, 7 red and 2 white balls. One ball is taken out without looking. What is the probability that it is green? (a) 3/4 (b) 1/12 (c) 1/3 (d) 1/4
  34. 34.A bag has 3 yellow, 9 red and 3 green balls. One ball is taken out without looking. What is the probability that it is red? (a) 3/5 (b) 2/5 (c) 1/3 (d) 2/3
  35. 35.A bag has 3 blue, 8 white and 2 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 2/11 (b) 11/13 (c) 1/3 (d) 2/13
  36. 36.A bag has 4 blue, 5 yellow and 3 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 7/12 (c) 5/12 (d) 5/7
  37. 37.A bag has 7 white, 3 red and 3 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 3/10 (b) 1/3 (c) 10/13 (d) 3/13
  38. 38.A bag has 5 blue, 3 green and 2 yellow balls. One ball is taken out without looking. What is the probability that it is green? (a) 3/7 (b) 3/10 (c) 1/3 (d) 7/10
  39. 39.A bag has 8 green, 6 blue and 5 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 8/11 (c) 8/19 (d) 11/19
  40. 40.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 1/11 (b) 1/6 (c) 6/11 (d) 7/36

Answer key

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

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