Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 450 · 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 9 red, 6 white and 2 blue balls. One ball is taken out without looking. What is the probability that it is not red? (a) 9/17 (b) 8/9 (c) 8/17 (d) 1/3
2. 2.A bag has 9 yellow, 7 green and 3 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 12/19 (b) 7/19 (c) 1/3 (d) 7/12
3. 3.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/3 (b) 3/4 (c) 1/4 (d) 1/2
4. 4.A bag has 2 red, 9 white and 2 blue balls. One ball is taken out without looking. What is the probability that it is not white? (a) 4/13 (b) 4/9 (c) 1/3 (d) 9/13
5. 5.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/11 (b) 1/12 (c) 1/18 (d) 1/36
6. 6.A bag has 8 white, 3 red and 2 green balls. One ball is taken out without looking. What is the probability that it is not red? (a) 10/13 (b) 11/13 (c) 1/3 (d) 3/13
7. 7.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/8 (b) 1/4 (c) 7/8 (d) 1/7
8. 8.Three coins are tossed together. What is the probability of getting exactly one head? (a) 5/8 (b) 3/8 (c) 3/5 (d) 1/4
9. 9.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/11 (b) 1/6 (c) 5/11 (d) 5/36
10. 10.A bag has 6 green, 4 white and 3 blue balls. One ball is taken out without looking. What is the probability that it is white? (a) 4/9 (b) 9/13 (c) 4/13 (d) 1/3
11. 11.A bag has 2 blue, 9 yellow and 4 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 11/15 (b) 4/11 (c) 1/3 (d) 4/15
12. 12.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/2 (b) 2/3 (c) 1/6 (d) 1/3
13. 13.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
14. 14.A bag has 7 blue, 5 yellow and 7 green balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 1/3 (b) 5/19 (c) 5/14 (d) 14/19
15. 15.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
16. 16.Two dice are rolled together. What is the probability that the two numbers add up to 5? (a) 1/9 (b) 1/11 (c) 5/36 (d) 4/11
17. 17.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/8 (b) 3/8 (c) 1/4 (d) 3/4
18. 18.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/12 (b) 1/18 (c) 1/11 (d) 2/11
19. 19.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 2/3 (b) 5/6 (c) 1/4 (d) 1/3
20. 20.A bag has 3 red, 2 blue and 5 white balls. One ball is taken out without looking. What is the probability that it is red? (a) 3/7 (b) 7/10 (c) 3/10 (d) 1/3
21. 21.A bag has 8 red, 5 green and 8 yellow balls. One ball is taken out without looking. What is the probability that it is not red? (a) 2/3 (b) 1/3 (c) 8/21 (d) 13/21
22. 22.A fair dice is rolled once. What is the probability of getting a prime number? (a) 2/3 (b) 1/3 (c) 1/2 (d) 1/6
23. 23.A bag has 8 yellow, 7 white and 5 green balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 2/5 (b) 3/5 (c) 2/3 (d) 1/3
24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 1/11 (b) 1/18 (c) 1/12 (d) 2/11
25. 25.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 1/11 (b) 6/11 (c) 7/36 (d) 1/6
26. 26.A bag has 9 green, 3 red and 3 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 4/5 (b) 1/3 (c) 1/5 (d) 1/4
27. 27.A bag has 4 green, 2 blue and 8 white balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/7 (b) 1/3 (c) 6/7 (d) 1/6
28. 28.A bag has 6 blue, 9 green and 3 white balls. One ball is taken out without looking. What is the probability that it is not green? (a) 1/2 (b) 1/18 (c) 5/9 (d) 1/3
29. 29.A fair dice is rolled once. What is the probability of getting a number less than 2? (a) 1/3 (b) 1/5 (c) 5/6 (d) 1/6
30. 30.A bag has 9 red, 2 green and 5 white balls. One ball is taken out without looking. What is the probability that it is not white? (a) 3/4 (b) 11/16 (c) 1/3 (d) 5/16
31. 31.A bag has 9 yellow, 9 blue and 9 white balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 19/27 (b) 2/3 (c) 1/27 (d) 1/3
32. 32.A bag has 7 red, 3 yellow and 7 blue balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 10/17 (c) 11/17 (d) 7/17
33. 33.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 4/11 (b) 1/11 (c) 1/9 (d) 5/36
34. 34.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/6 (b) 1/3 (c) 2/3 (d) 1/2
35. 35.A fair dice is rolled once. What is the probability of getting a number less than 4? (a) 1/3 (b) 1/2 (c) 2/3 (d) 1/6
36. 36.A bag has 7 white, 5 blue and 2 red balls. One ball is taken out without looking. What is the probability that it is red? (a) 1/7 (b) 6/7 (c) 1/3 (d) 1/6
37. 37.A bag has 4 blue, 7 white and 5 red balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/4 (b) 13/16 (c) 3/4 (d) 1/3
38. 38.Three coins are tossed together. What is the probability of getting at least one head? (a) 1/4 (b) 3/8 (c) 7/8 (d) 1/8
39. 39.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/12 (b) 1/36 (c) 1/11 (d) 1/18
40. 40.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/3 (b) 3/4 (c) 1/4 (d) 1/2

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