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Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 490 · 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 2? (a) 1/12 (b) 1/11 (c) 1/36 (d) 1/18
  2. 2.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
  3. 3.A fair dice is rolled once. What is the probability of getting an odd number? (a) 2/3 (b) 1/2 (c) 1/3 (d) 1/6
  4. 4.A bag has 3 blue, 4 yellow and 4 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 8/11 (b) 4/11 (c) 7/11 (d) 1/3
  5. 5.A bag has 9 green, 2 yellow and 8 blue balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 2/17 (b) 17/19 (c) 1/3 (d) 2/19
  6. 6.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
  7. 7.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/3 (b) 1/2 (c) 2/3 (d) 1/6
  8. 8.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
  9. 9.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/3 (b) 1/2 (c) 3/4 (d) 1/4
  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) 1/4 (d) 3/4
  11. 11.A bag has 6 yellow, 7 green and 4 white balls. One ball is taken out without looking. What is the probability that it is not green? (a) 7/17 (b) 11/17 (c) 10/17 (d) 1/3
  12. 12.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/11 (b) 1/18 (c) 2/11 (d) 1/12
  13. 13.A bag has 4 red, 8 white and 7 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 12/19 (c) 7/19 (d) 7/12
  14. 14.A bag has 8 red, 9 green and 5 white balls. One ball is taken out without looking. What is the probability that it is red? (a) 7/11 (b) 4/7 (c) 4/11 (d) 1/3
  15. 15.A bag has 5 white, 7 blue and 7 green balls. One ball is taken out without looking. What is the probability that it is not white? (a) 14/19 (b) 1/3 (c) 5/19 (d) 15/19
  16. 16.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/6 (b) 2/3 (c) 1/2 (d) 1/3
  17. 17.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 7/8 (c) 1/7 (d) 1/8
  18. 18.A bag has 4 blue, 5 red and 3 white balls. One ball is taken out without looking. What is the probability that it is red? (a) 5/12 (b) 1/3 (c) 5/7 (d) 7/12
  19. 19.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) 1/4 (d) 3/8
  20. 20.Three coins are tossed together. What is the probability of getting exactly one head? (a) 3/5 (b) 1/4 (c) 5/8 (d) 3/8
  21. 21.A bag has 2 yellow, 9 green and 4 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/3 (b) 4/5 (c) 4/15 (d) 11/15
  22. 22.A bag has 7 red, 5 white and 5 yellow balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 5/12 (c) 5/17 (d) 12/17
  23. 23.A bag has 4 red, 2 green and 2 white balls. One ball is taken out without looking. What is the probability that it is red? (a) 1/8 (b) 1/2 (c) 5/8 (d) 1/3
  24. 24.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/3 (b) 5/6 (c) 2/3 (d) 1/4
  25. 25.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 1/9 (b) 4/11 (c) 5/36 (d) 1/11
  26. 26.A bag has 5 white, 2 red and 7 green balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/7 (b) 1/3 (c) 13/14 (d) 6/7
  27. 27.A fair dice is rolled once. What is the probability of getting a number less than 3? (a) 2/3 (b) 1/2 (c) 1/6 (d) 1/3
  28. 28.A bag has 9 yellow, 7 red and 4 white balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 9/20 (c) 9/11 (d) 11/20
  29. 29.A bag has 3 white, 3 green and 9 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 13/15 (b) 1/3 (c) 4/5 (d) 1/5
  30. 30.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 1/11 (b) 6/11 (c) 1/6 (d) 7/36
  31. 31.A bag has 9 green, 8 yellow and 2 red balls. One ball is taken out without looking. What is the probability that it is red? (a) 2/19 (b) 17/19 (c) 1/3 (d) 2/17
  32. 32.A bag has 7 yellow, 9 white and 2 red balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 11/18 (b) 1/3 (c) 7/11 (d) 7/18
  33. 33.A fair dice is rolled once. What is the probability of getting a number greater than 2? (a) 1/4 (b) 5/6 (c) 1/3 (d) 2/3
  34. 34.A bag has 7 blue, 2 yellow and 3 red balls. One ball is taken out without looking. What is the probability that it is blue? (a) 5/12 (b) 2/3 (c) 7/12 (d) 1/3
  35. 35.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/9 (b) 1/11 (c) 1/12 (d) 3/11
  36. 36.A bag has 9 blue, 4 red and 6 white balls. One ball is taken out without looking. What is the probability that it is not red? (a) 15/19 (b) 16/19 (c) 1/3 (d) 4/19
  37. 37.A bag has 9 white, 2 blue and 7 red balls. One ball is taken out without looking. What is the probability that it is red? (a) 11/18 (b) 7/11 (c) 7/18 (d) 1/3
  38. 38.A bag has 5 white, 5 yellow and 4 red balls. One ball is taken out without looking. What is the probability that it is white? (a) 5/9 (b) 5/14 (c) 1/3 (d) 9/14
  39. 39.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/4 (b) 1/8 (c) 7/8 (d) 3/8
  40. 40.A bag has 6 red, 5 yellow and 2 blue balls. One ball is taken out without looking. What is the probability that it is red? (a) 7/13 (b) 1/3 (c) 6/13 (d) 6/7

Answer key

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

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