PassNova has 8 free KS3 Maths practice questions on Probability, each with a clear explanation. Practise them in the browser with instant feedback — 100% free, no sign-up, on any device. Updated for 2026.
Probability: example questions & answers
8 worked examples with answers and explanations below. Practise them in the browser with instant feedback on every answer.
A fair six-sided dice is rolled. What is the probability of rolling a 4?
- A1/4
- B1/6✓
- C1/2
- D4/6
Answer: There is one '4' out of six equally likely outcomes, so the probability is 1/6.
What is the probability of an event that is certain to happen?
- A0
- B0.5
- C1✓
- D2
Answer: Probabilities range from 0 (impossible) to 1 (certain). A certain event has probability 1.
A bag has 3 red and 2 blue balls. What is the probability of picking a red ball?
- A2/5
- B1/2
- C3/2
- D3/5✓
Answer: There are 5 balls in total and 3 are red, so P(red) = 3/5.
A coin is flipped. What is the probability of getting tails?
- A1/4
- B1/2✓
- C1
- D2
Answer: A fair coin has two equally likely outcomes, so P(tails) = 1/2.
The probabilities of all outcomes of an event must add up to:
- A0
- B1✓
- C10
- D100
Answer: The probabilities of all possible outcomes of an event always sum to 1.
Two fair six-sided dice are rolled and both scores are recorded. How many equally likely outcomes are there in the sample space?
- A12
- B11
- C36✓
- D6
Answer: Each of the 6 scores on the first dice can pair with each of the 6 on the second, giving 6 × 6 = 36 equally likely outcomes. Adding the sixes gives 12, and 11 is how many different totals are possible, not how many outcomes.
A fair coin is flipped and a fair four-sided spinner numbered 1 to 4 is spun. What is the probability of getting a head and a 3?
- A1/8✓
- B3/4
- C1/6
- D1/2
Answer: For two independent events happening together the probabilities are multiplied: 1/2 × 1/4 = 1/8. Adding them gives 3/4, which is larger than either event on its own and so cannot be right.
Two fair six-sided dice are rolled and the two scores are added. What is the probability that the total is 7?
- A1/12
- B7/36
- C1/36
- D1/6✓
Answer: Six of the 36 possible outcomes give a total of 7: 1 and 6, 2 and 5, 3 and 4, and each of those the other way round. That makes the probability 6/36, which simplifies to 1/6.