Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 141 · 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 7 white, 7 red and 7 green balls. One ball is taken out without looking. What is the probability that it is green? (a) 1/2 (b) 8/21 (c) 1/3 (d) 2/3
2. 2.A bag has 9 red, 4 blue and 3 white balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 13/16 (b) 3/4 (c) 1/4 (d) 1/3
3. 3.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 7/8 (c) 1/8 (d) 1/7
4. 4.A fair dice is rolled once. What is the probability of getting a prime number? (a) 2/3 (b) 1/2 (c) 1/6 (d) 1/3
5. 5.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
6. 6.A bag has 5 blue, 2 white and 6 red balls. One ball is taken out without looking. What is the probability that it is blue? (a) 8/13 (b) 5/13 (c) 1/3 (d) 5/8
7. 7.A fair dice is rolled once. What is the probability of getting a number less than 3? (a) 1/2 (b) 1/3 (c) 2/3 (d) 1/6
8. 8.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/2 (b) 1/6 (c) 2/3 (d) 1/3
9. 9.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/2 (b) 2/3 (c) 1/3 (d) 1/6
10. 10.Two coins are tossed together. What is the probability of getting exactly one head? (a) 1/3 (b) 2/3 (c) 1/2 (d) 1/4
11. 11.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 1/3 (b) 2/3 (c) 5/6 (d) 1/4
12. 12.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 5/11 (b) 1/6 (c) 5/36 (d) 1/11
13. 13.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
14. 14.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/6 (b) 1/2 (c) 1/3 (d) 2/3
15. 15.Two dice are rolled together. What is the probability that the two numbers add up to 8? (a) 1/6 (b) 1/11 (c) 5/11 (d) 5/36
16. 16.A bag has 7 blue, 9 red and 6 green balls. One ball is taken out without looking. What is the probability that it is blue? (a) 7/15 (b) 15/22 (c) 1/3 (d) 7/22
17. 17.A bag has 7 yellow, 2 white and 6 green balls. One ball is taken out without looking. What is the probability that it is yellow? (a) 8/15 (b) 1/3 (c) 7/15 (d) 7/8
18. 18.A bag has 4 green, 2 red and 5 white balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 2/11 (c) 9/11 (d) 10/11
19. 19.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 1/11 (b) 7/36 (c) 1/6 (d) 6/11
20. 20.A bag has 7 white, 3 green and 3 yellow balls. One ball is taken out without looking. What is the probability that it is not white? (a) 7/13 (b) 1/3 (c) 6/7 (d) 6/13
21. 21.A bag has 9 yellow, 7 green and 7 red balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 9/23 (b) 14/23 (c) 1/3 (d) 15/23
22. 22.A bag has 5 blue, 5 red and 7 green balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 12/17 (c) 13/17 (d) 5/17
23. 23.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/12 (b) 1/11 (c) 3/11 (d) 1/9
24. 24.Two dice are rolled together. What is the probability that the two numbers add up to 4? (a) 1/12 (b) 1/9 (c) 1/11 (d) 3/11
25. 25.A bag has 9 white, 2 yellow and 3 red balls. One ball is taken out without looking. What is the probability that it is not yellow? (a) 1/3 (b) 13/14 (c) 1/7 (d) 6/7
26. 26.A bag has 6 yellow, 7 green and 9 red balls. One ball is taken out without looking. What is the probability that it is green? (a) 7/22 (b) 15/22 (c) 1/3 (d) 7/15
27. 27.A bag has 3 yellow, 2 white and 2 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 5/7 (b) 2/5 (c) 2/7 (d) 1/3
28. 28.A fair dice is rolled once. What is the probability of getting a number greater than 4? (a) 1/6 (b) 1/2 (c) 2/3 (d) 1/3
29. 29.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/4 (b) 1/3 (c) 1/2 (d) 2/3
30. 30.A fair dice is rolled once. What is the probability of getting a number greater than 3? (a) 1/2 (b) 1/3 (c) 1/6 (d) 2/3
31. 31.A bag has 7 red, 2 white and 3 blue balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 3/4 (b) 5/6 (c) 1/3 (d) 1/4
32. 32.Two dice are rolled together. What is the probability that the two numbers add up to 11? (a) 2/11 (b) 1/12 (c) 1/11 (d) 1/18
33. 33.A bag has 3 red, 3 green and 3 yellow balls. One ball is taken out without looking. What is the probability that it is not green? (a) 1/9 (b) 1/3 (c) 7/9 (d) 2/3
34. 34.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/36 (b) 1/12 (c) 1/18 (d) 1/11
35. 35.A fair dice is rolled once. What is the probability of getting a number less than 5? (a) 5/6 (b) 2/3 (c) 1/3 (d) 1/4
36. 36.A bag has 4 red, 9 blue and 3 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 7/16 (b) 1/3 (c) 5/8 (d) 9/16
37. 37.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
38. 38.A bag has 9 blue, 6 red and 6 green balls. One ball is taken out without looking. What is the probability that it is blue? (a) 1/3 (b) 4/7 (c) 3/4 (d) 3/7
39. 39.A bag has 8 yellow, 8 white and 8 red balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/24 (b) 2/3 (c) 1/3 (d) 17/24
40. 40.A bag has 8 white, 3 red and 3 green balls. One ball is taken out without looking. What is the probability that it is white? (a) 3/7 (b) 1/3 (c) 4/7 (d) 9/14

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