Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 135 · 40 questions

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.

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

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