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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 246 · 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 red and 7 green balls. One ball is taken out without looking. What is the probability that it is not red? (a) 4/5 (b) 1/3 (c) 17/20 (d) 1/5
  2. 2.A bag has 6 red, 6 yellow and 8 green balls. One ball is taken out without looking. What is the probability that it is red? (a) 3/10 (b) 3/7 (c) 7/10 (d) 1/3
  3. 3.A fair dice is rolled once. What is the probability of getting a number greater than 4? (a) 1/3 (b) 2/3 (c) 1/6 (d) 1/2
  4. 4.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 6/11 (b) 1/11 (c) 7/36 (d) 1/6
  5. 5.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
  6. 6.Three coins are tossed together. What is the probability of getting at least one head? (a) 3/8 (b) 1/4 (c) 1/8 (d) 7/8
  7. 7.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 4/11 (b) 5/36 (c) 1/9 (d) 1/11
  8. 8.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/6 (b) 1/2 (c) 1/3 (d) 2/3
  9. 9.A bag has 3 red, 2 white and 4 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 4/5 (b) 4/9 (c) 1/3 (d) 5/9
  10. 10.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/2 (b) 1/3 (c) 3/4 (d) 1/4
  11. 11.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 1/11 (b) 5/36 (c) 1/6 (d) 5/11
  12. 12.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 5/36 (b) 4/11 (c) 1/11 (d) 1/9
  13. 13.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
  14. 14.A fair dice is rolled once. What is the probability of getting an even number? (a) 2/3 (b) 1/3 (c) 1/2 (d) 1/6
  15. 15.A bag has 7 white, 3 yellow and 2 red balls. One ball is taken out without looking. What is the probability that it is not white? (a) 5/7 (b) 5/12 (c) 7/12 (d) 1/3
  16. 16.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/3 (b) 1/2 (c) 2/3 (d) 1/6
  17. 17.A bag has 2 yellow, 9 white and 9 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 9/11 (c) 9/20 (d) 11/20
  18. 18.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/12 (b) 1/11 (c) 1/9 (d) 3/11
  19. 19.A bag has 7 yellow, 7 green and 3 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 10/17 (b) 7/10 (c) 7/17 (d) 1/3
  20. 20.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/6 (b) 1/11 (c) 5/36 (d) 5/11
  21. 21.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/4 (b) 1/8 (c) 3/4 (d) 3/8
  22. 22.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 2/3 (b) 1/3 (c) 5/6 (d) 1/4
  23. 23.A bag has 4 red, 9 blue and 2 green balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 2/3 (b) 3/5 (c) 1/3 (d) 2/5
  24. 24.A bag has 4 red, 5 white and 3 green balls. One ball is taken out without looking. What is the probability that it is red? (a) 1/3 (b) 1/2 (c) 2/3 (d) 5/12
  25. 25.A bag has 2 red, 9 yellow and 9 blue balls. One ball is taken out without looking. What is the probability that it is red? (a) 9/10 (b) 1/3 (c) 1/10 (d) 1/9
  26. 26.A bag has 7 red, 4 green and 5 yellow balls. One ball is taken out without looking. What is the probability that it is red? (a) 9/16 (b) 1/3 (c) 7/16 (d) 7/9
  27. 27.Two coins are tossed together. What is the probability of getting at least one head? (a) 3/4 (b) 1/4 (c) 1/3 (d) 1/2
  28. 28.A bag has 4 blue, 2 red and 4 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/3 (b) 7/10 (c) 2/5 (d) 3/5
  29. 29.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/4 (b) 1/3 (c) 2/3 (d) 1/2
  30. 30.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/12 (b) 1/11 (c) 2/11 (d) 1/18
  31. 31.A bag has 2 blue, 6 red and 7 white balls. One ball is taken out without looking. What is the probability that it is red? (a) 2/5 (b) 2/3 (c) 1/3 (d) 3/5
  32. 32.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
  33. 33.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
  34. 34.A bag has 9 blue, 4 green and 7 white balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 3/5 (b) 11/20 (c) 1/3 (d) 9/20
  35. 35.A bag has 8 blue, 8 red and 8 yellow balls. One ball is taken out without looking. What is the probability that it is red? (a) 2/3 (b) 1/2 (c) 3/8 (d) 1/3
  36. 36.A bag has 2 red, 5 green and 5 blue balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 5/12 (c) 7/12 (d) 5/7
  37. 37.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/11 (b) 1/36 (c) 1/12 (d) 1/18
  38. 38.A bag has 6 white, 6 yellow and 4 blue balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 3/5 (b) 5/8 (c) 3/8 (d) 1/3
  39. 39.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 2/3 (b) 1/3 (c) 1/4 (d) 1/2
  40. 40.A fair dice is rolled once. What is the probability of getting a number less than 5? (a) 5/6 (b) 1/4 (c) 2/3 (d) 1/3

Answer key

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

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