Probability Worksheet for Class 8 Maths Olympiad

Maths Olympiad topic 24: Probability basics · Set 240 · 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 yellow, 5 blue and 5 red balls. One ball is taken out without looking. What is the probability that it is not red? (a) 1/3 (b) 7/9 (c) 13/18 (d) 5/18
2. 2.Two dice are rolled together. What is the probability that the two numbers add up to 2? (a) 1/11 (b) 1/18 (c) 1/12 (d) 1/36
3. 3.Three coins are tossed together. What is the probability of getting at least one head? (a) 3/8 (b) 1/8 (c) 7/8 (d) 1/4
4. 4.A bag has 3 blue, 8 red and 2 green balls. One ball is taken out without looking. What is the probability that it is not green? (a) 11/13 (b) 1/3 (c) 2/13 (d) 12/13
5. 5.A fair dice is rolled once. What is the probability of getting an even number? (a) 1/3 (b) 1/6 (c) 2/3 (d) 1/2
6. 6.Two dice are rolled together. What is the probability that the two numbers add up to 3? (a) 1/12 (b) 1/18 (c) 2/11 (d) 1/11
7. 7.A fair dice is rolled once. What is the probability of getting a number greater than 3? (a) 2/3 (b) 1/2 (c) 1/3 (d) 1/6
8. 8.Two coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 1/4 (b) 1/2 (c) 2/3 (d) 1/3
9. 9.A fair dice is rolled once. What is the probability of getting a multiple of 3? (a) 1/6 (b) 2/3 (c) 1/3 (d) 1/2
10. 10.Two dice are rolled together. What is the probability that the two numbers add up to 9? (a) 1/9 (b) 5/36 (c) 1/11 (d) 4/11
11. 11.Two dice are rolled together. What is the probability that the two numbers add up to 7? (a) 1/6 (b) 6/11 (c) 7/36 (d) 1/11
12. 12.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
13. 13.A bag has 2 yellow, 3 white and 4 green balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/3 (b) 2/3 (c) 4/9 (d) 1/2
14. 14.Two coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 1/3 (c) 1/2 (d) 3/4
15. 15.Two dice are rolled together. What is the probability that the two numbers add up to 6? (a) 5/36 (b) 1/6 (c) 5/11 (d) 1/11
16. 16.A fair dice is rolled once. What is the probability of getting a prime number? (a) 1/3 (b) 1/6 (c) 1/2 (d) 2/3
17. 17.Two dice are rolled together. What is the probability that the two numbers add up to 12? (a) 1/18 (b) 1/12 (c) 1/36 (d) 1/11
18. 18.Two coins are tossed together. What is the probability of getting exactly one head? (a) 2/3 (b) 1/4 (c) 1/3 (d) 1/2
19. 19.A bag has 5 red, 6 green and 7 blue balls. One ball is taken out without looking. What is the probability that it is not green? (a) 2/3 (b) 13/18 (c) 1/3 (d) 1/18
20. 20.A bag has 5 green, 2 blue and 7 yellow balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 6/7 (c) 1/7 (d) 13/14
21. 21.A fair dice is rolled once. What is the probability of getting an odd number? (a) 1/2 (b) 1/3 (c) 1/6 (d) 2/3
22. 22.A bag has 4 red, 3 green and 6 blue balls. One ball is taken out without looking. What is the probability that it is blue? (a) 6/7 (b) 7/13 (c) 6/13 (d) 1/3
23. 23.Two coins are tossed together. What is the probability of getting at least one head? (a) 1/3 (b) 3/4 (c) 1/2 (d) 1/4
24. 24.Three coins are tossed together. What is the probability of getting at least one head and at least one tail? (a) 3/4 (b) 1/8 (c) 1/4 (d) 3/8
25. 25.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
26. 26.A bag has 4 green, 8 red and 8 yellow balls. One ball is taken out without looking. What is the probability that it is not red? (a) 2/5 (b) 1/3 (c) 3/5 (d) 13/20
27. 27.A bag has 2 red, 7 blue and 9 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 7/18 (b) 7/11 (c) 11/18 (d) 1/3
28. 28.A bag has 9 yellow, 7 blue and 2 green balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 11/18 (b) 1/3 (c) 2/3 (d) 7/18
29. 29.Two dice are rolled together. What is the probability that the two numbers add up to 10? (a) 1/9 (b) 1/11 (c) 3/11 (d) 1/12
30. 30.A bag has 2 green, 7 white and 6 yellow balls. One ball is taken out without looking. What is the probability that it is green? (a) 13/15 (b) 1/3 (c) 2/13 (d) 2/15
31. 31.Three coins are tossed together. What is the probability of getting a head on every coin? (a) 1/4 (b) 1/7 (c) 7/8 (d) 1/8
32. 32.A bag has 2 white, 4 yellow and 8 blue balls. One ball is taken out without looking. What is the probability that it is not white? (a) 1/7 (b) 6/7 (c) 13/14 (d) 1/3
33. 33.A fair dice is rolled once. What is the probability of getting a factor of 6? (a) 2/3 (b) 1/3 (c) 5/6 (d) 1/4
34. 34.A bag has 2 green, 5 white and 6 red balls. One ball is taken out without looking. What is the probability that it is white? (a) 8/13 (b) 5/13 (c) 1/3 (d) 5/8
35. 35.A bag has 3 white, 8 blue and 3 yellow balls. One ball is taken out without looking. What is the probability that it is blue? (a) 9/14 (b) 1/3 (c) 4/7 (d) 3/7
36. 36.A bag has 3 white, 8 green 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) 9/13 (d) 8/13
37. 37.A bag has 9 blue, 3 yellow and 6 white balls. One ball is taken out without looking. What is the probability that it is white? (a) 1/2 (b) 7/18 (c) 2/3 (d) 1/3
38. 38.A bag has 9 red, 2 white and 6 blue balls. One ball is taken out without looking. What is the probability that it is white? (a) 2/17 (b) 2/15 (c) 1/3 (d) 15/17
39. 39.A bag has 4 white, 3 red and 9 green balls. One ball is taken out without looking. What is the probability that it is not red? (a) 7/8 (b) 1/3 (c) 3/16 (d) 13/16
40. 40.A bag has 4 blue, 4 red and 7 white balls. One ball is taken out without looking. What is the probability that it is not blue? (a) 1/3 (b) 11/15 (c) 4/15 (d) 4/5

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