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GCSE Maths Foundation: Probability practice questions
Ten free GCSE Maths Foundation tier questions on the probability scale, combined events, sample spaces, relative frequency and expected outcomes, each with a worked solution. Suitable for AQA, Edexcel and OCR.
Questions originales rédigées par les professeurs Studoli dans l’esprit de l’examen GCSE. Ce ne sont pas des sujets officiels.
Mode chronométré
10 questions en 15 minutes, une question à la fois. Vos réponses sont corrigées à la fin ou quand le temps est écoulé.
Notion: Probability
1. A fair dice is rolled. What is the probability of an even number?
Correction
B. 1/2
- The even numbers are 2, 4 and 6: 3 outcomes out of 6.
- 3/6 = 1/2.
Notion: Probability
2. The probability that a spinner lands on red is 0.35. What is the probability that it does not land on red?
Correction
A. 0.65
- P(not A) = 1 − P(A).
- 1 − 0.35 = 0.65.
Notion: Probability
3. A bag holds 3 red, 5 blue and 2 green counters. One is picked at random. Find P(green).
Correction
D. 1/5
- There are 3 + 5 + 2 = 10 counters and 2 are green.
- 2/10 = 1/5.
Notion: Combined events
4. A fair coin is flipped twice. What is the probability of two heads?
Correction
C. 1/4
- The outcomes are HH, HT, TH and TT.
- One of the four is HH, so 1/4.
Notion: Expected outcomes
5. The probability of winning a game is 0.2. How many wins would you expect in 50 games?
Correction
B. 10
- Expected number = probability × number of trials.
- 0.2 × 50 = 10.
Notion: Sample space
6. A coin is flipped and a dice is rolled. How many possible outcomes are there?
Correction
A. 12
- The coin has 2 outcomes and the dice has 6.
- 2 × 6 = 12.
Notion: Relative frequency
7. A drawing pin lands point up 18 times in 60 throws. What is the relative frequency of point up?
Correction
D. 0.3
- Relative frequency = number of times ÷ number of trials.
- 18 ÷ 60 = 0.3.
Notion: Mutually exclusive events
8. A and B are mutually exclusive. P(A) = 0.3 and P(B) = 0.45. Find P(A or B).
Correction
C. 0.75
- For mutually exclusive events, P(A or B) = P(A) + P(B).
- 0.3 + 0.45 = 0.75.
Notion: Probability
9. A spinner can land on red, blue or green. P(red) = 0.4 and P(blue) = 0.25. Find P(green).
Correction
B. 0.35
- The probabilities add up to 1.
- 1 − 0.4 − 0.25 = 0.35.
Notion: Probability scale
10. An event has a probability of 0. How is it described?
Correction
A. Impossible
- A probability of 0 means the event cannot happen.
- A probability of 1 means it is certain.