1. A and B are independent events with P(A) = 0.3 and P(B) = 0.6. What is P(A and B)?
- A0.9
- B0.72
- C0.18
- D0.09
Show answer
Answer: C. For independent events multiply: 0.3 × 0.6 = 0.18. Adding (0.9) is for mutually exclusive events with "or".
By Team Megalecture · Updated 4 Nov 2026
20 exam-style questions on Probability, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
20 questions · 2 topics · 10 per test
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
Answer: C. For independent events multiply: 0.3 × 0.6 = 0.18. Adding (0.9) is for mutually exclusive events with "or".
Answer: A. The probabilities of all outcomes add to 1: 1 − 0.35 − 0.4 = 0.25. 0.75 is P(red or blue).
Answer: A. P(rain tomorrow) = 0.28 + 0.18 = 0.46. P(rain today | rain tomorrow) = 0.28 ÷ 0.46 = 0.609. 0.7 is the probability the other way round.
Answer: B. There are 36 equally likely outcomes, and 8 comes from (2, 6), (3, 5), (4, 4), (5, 3), (6, 2): 5 outcomes, so 5/36. Forgetting that (2, 6) and (6, 2) are different gives too few.
Answer: A. P(red then blue) + P(blue then red) = 5/8 × 3/7 + 3/8 × 5/7 = 30/56 = 15/28. 15/56 counts only one of the two orders.
Answer: C. Tea or coffee = 28 + 22 − 9 = 41, so 50 − 41 = 9 like neither. Adding 28 + 22 = 50 counts the 9 who like both twice.
Answer: C. The sample space has 4 × 2 = 8 outcomes, and (2, H) and (4, H) are the successful ones: 2/8 = 1/4. Also ½ × ½ = ¼.
Answer: D. 5/8 × 4/7 = 20/56 = 5/14. After one red is taken there are 4 red out of 7 left. 25/64 assumes the first counter is replaced.
Answer: B. There are 18 + 14 = 32 bike owners, and 18 are boys: 18/32 = 9/16. 18/25 is the probability that a boy owns a bike.
Answer: D. 3/8 of the total is 15, so the total is 40 and there are 40 − 15 = 25 blue counters. 40 is the total, not the blue counters.
20, each with the answer and a short explanation, across 2 topics: P1–P5 Probability and expected outcomes, P6–P9 Combined events and conditional probability. Every chapter test draws ten of them, so you can take it many times.
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
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