Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 315 · 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 5 green, 4 blue and 9 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/2 (b) 1/3 (c) 1/18 (d) 5/9
2. 2.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/3 (b) 2/3 (c) 1/6 (d) 1/2
3. 3.A bag has 3 green, 8 red and 2 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 2/11 (b) 1/3 (c) 2/13 (d) 11/13
4. 4.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) 1/2 (d) 1/4
5. 5.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
6. 6.A bag has 2 red, 3 yellow and 7 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 7/12 (b) 5/7 (c) 5/12 (d) 1/3
7. 7.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/3 (b) 1/2 (c) 2/3 (d) 1/6
8. 8.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/11 (b) 5/11 (c) 1/6 (d) 5/36
9. 9.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/3 (b) 2/3 (c) 1/6 (d) 1/2
10. 10.A fair dice is rolled once. What is the probability of getting a number greater than 1? (a) 5/6 (b) 1/3 (c) 1/5 (d) 1/6
11. 11.A bag has 9 green, 4 yellow and 2 white balls. One ball is taken out without looking. What is the probability that it is not green? (a) 3/5 (b) 2/5 (c) 2/3 (d) 1/3
12. 12.A bag has 2 blue, 5 yellow and 4 green balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 9/11 (b) 10/11 (c) 1/3 (d) 2/11
13. 13.A bag has 5 red, 2 white and 4 blue balls. One ball is taken out without looking. What is the probability that it is red? (a) 1/3 (b) 5/11 (c) 5/6 (d) 6/11
14. 14.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 1/11 (b) 1/9 (c) 5/36 (d) 4/11
15. 15.A bag has 4 green, 2 yellow and 2 red balls. One ball is taken out without looking. What is the probability that it is not red? (a) 3/4 (b) 1/3 (c) 7/8 (d) 1/4
16. 16.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 3/4 (c) 1/3 (d) 1/2
17. 17.Three coins are tossed together. What is the probability of getting exactly one head? (a) 3/8 (b) 1/4 (c) 3/5 (d) 5/8
18. 18.A bag has 4 green, 4 blue and 4 red balls. One ball is taken out without looking. What is the probability that it is blue? (a) 5/12 (b) 2/3 (c) 1/2 (d) 1/3
19. 19.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/18 (b) 1/36 (c) 1/11 (d) 1/12
20. 20.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/8 (b) 7/8 (c) 1/4 (d) 3/8
21. 21.A bag has 5 red, 7 blue and 7 white balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 13/19 (c) 12/19 (d) 7/19
22. 22.A bag has 6 red, 6 white and 6 blue balls. One ball is taken out without looking. What is the probability that it is red? (a) 7/18 (b) 1/2 (c) 2/3 (d) 1/3
23. 23.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/3 (b) 2/3 (c) 1/2 (d) 1/6
24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/12 (b) 1/18 (c) 1/36 (d) 1/11
25. 25.A bag has 4 red, 3 yellow and 7 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 1/2 (c) 1/14 (d) 4/7
26. 26.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 3/11 (b) 1/12 (c) 1/9 (d) 1/11
27. 27.A bag has 9 red, 5 green and 8 blue balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 17/22 (c) 5/17 (d) 5/22
28. 28.A bag has 8 white, 5 yellow and 7 red balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 13/20 (c) 7/10 (d) 7/20
29. 29.A fair dice is rolled once. What is the probability of getting a number less than 2? (a) 5/6 (b) 1/5 (c) 1/3 (d) 1/6
30. 30.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
31. 31.A bag has 8 blue, 3 red and 2 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 9/13 (b) 5/13 (c) 1/3 (d) 8/13
32. 32.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 2/11 (b) 1/11 (c) 1/12 (d) 1/18
33. 33.A bag has 8 blue, 7 yellow and 6 white balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 8/21 (b) 2/3 (c) 1/3 (d) 1/2
34. 34.A bag has 9 green, 2 blue and 3 white balls. One ball is taken out without looking. What is the probability that it is blue? (a) 6/7 (b) 1/3 (c) 1/6 (d) 1/7
35. 35.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 1/11 (b) 1/6 (c) 5/11 (d) 5/36
36. 36.A bag has 8 white, 2 blue and 4 green balls. One ball is taken out without looking. What is the probability that it is not white? (a) 4/7 (b) 1/3 (c) 3/7 (d) 3/4
37. 37.A bag has 8 green, 3 yellow and 6 blue balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/3 (b) 8/9 (c) 8/17 (d) 9/17
38. 38.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 5/36 (b) 1/11 (c) 1/9 (d) 4/11
39. 39.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 1/11 (b) 7/36 (c) 6/11 (d) 1/6
40. 40.A bag has 8 green, 6 yellow and 9 red balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 17/23 (b) 6/23 (c) 1/3 (d) 18/23

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