Free Grade 3 Conditional Probability Quizzes
Free Grade 3 quizzes for Conditional Probability: 12 real questions with a full answer key and worked solutions. Probability measures how likely something is, from 0 (impossible) to 1 (certain). P(event) = favourable outcomes ÷ total outcomes. For independent events, multiply.
Free
Core
15 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- RememberIdentify conditional probability
Identify conditional probability accurately in a familiar context.
Assessed by: Exit ticket of four short items
- UnderstandExplain conditional probability
Explain conditional probability accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate conditional probability
Calculate conditional probability accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare conditional probability
Compare conditional probability accurately in a familiar context.
Assessed by: Exit ticket of four short items
Prerequisites
Close these gaps first — each has its own free lesson, worksheet and quiz.
How Conditional Probability works
Probability measures how likely something is, from 0 (impossible) to 1 (certain). P(event) = favourable outcomes ÷ total outcomes. For independent events, multiply.
12 practice questions
Easy to hard, 24 marks in total. Try them first, then open the answers.
- 1.A bag has 6 red, 6 blue and 0 green counters. One is picked at random. Find P(red).[1]
- 2.A bag has 2 red, 2 blue and 1 green counters. One is picked at random. Find P(red).[1]
- 3.A bag has 4 red, 3 blue and 0 green counters. One is picked at random. Find P(red).[1]
- 4.A bag has 8 red, 4 blue and 1 green counters. One is picked at random. Find P(red).[1]
- 5.A bag has 6 red, 5 blue and 4 green counters. One is picked at random. Find P(red) and P(not red).[2]
- 6.A bag has 4 red, 1 blue and 3 green counters. One is picked at random. Find P(red) and P(not red).[2]
- 7.A bag has 8 red, 2 blue and 0 green counters. One is picked at random. Find P(red) and P(not red).[2]
- 8.A bag has 8 red, 4 blue and 0 green counters. One is picked at random. Find P(red) and P(not red).[2]
- 9.A bag has 6 red and 1 blue counters. Two are picked with replacement. Find P(both red).[3]
- 10.A bag has 3 red and 6 blue counters. Two are picked with replacement. Find P(both red).[3]
- 11.A bag has 1 red and 6 blue counters. Two are picked with replacement. Find P(both red).[3]
- 12.A bag has 5 red and 5 blue counters. Two are picked with replacement. Find P(both red).[3]
Show answers and working
1. P(red) = 1/2
Total counters = 12. P(red) = 6/12 = 1/2.
2. P(red) = 2/5
Total counters = 5. P(red) = 2/5 = 2/5.
3. P(red) = 4/7
Total counters = 7. P(red) = 4/7 = 4/7.
4. P(red) = 8/13
Total counters = 13. P(red) = 8/13 = 8/13.
5. P(red) = 2/5, P(not red) = 3/5
Total counters = 15. P(red) = 6/15 = 2/5. P(not red) = 1 − 2/5 = 3/5.
6. P(red) = 1/2, P(not red) = 1/2
Total counters = 8. P(red) = 4/8 = 1/2. P(not red) = 1 − 1/2 = 1/2.
7. P(red) = 4/5, P(not red) = 1/5
Total counters = 10. P(red) = 8/10 = 4/5. P(not red) = 1 − 4/5 = 1/5.
8. P(red) = 2/3, P(not red) = 1/3
Total counters = 12. P(red) = 8/12 = 2/3. P(not red) = 1 − 2/3 = 1/3.
9. 36/49
P(red) = 6/7 each time. Independent, so multiply: 6/7 × 6/7 = 36/49.
10. 1/9
P(red) = 3/9 each time. Independent, so multiply: 3/9 × 3/9 = 1/9.
11. 1/49
P(red) = 1/7 each time. Independent, so multiply: 1/7 × 1/7 = 1/49.
12. 1/4
P(red) = 5/10 each time. Independent, so multiply: 5/10 × 5/10 = 1/4.
Worked examples
A bag has 2 red, 4 blue and 5 green counters. One is picked at random. Find P(red).
- Total counters = 11.
- P(red) = 2/11 = 2/11.
- Answer: P(red) = 2/11
A bag has 2 red, 5 blue and 1 green counters. One is picked at random. Find P(red) and P(not red).
- Total counters = 8.
- P(red) = 2/8 = 1/4.
- P(not red) = 1 − 1/4 = 3/4.
- Answer: P(red) = 1/4, P(not red) = 3/4
A bag has 4 red and 3 blue counters. Two are picked with replacement. Find P(both red).
- P(red) = 4/7 each time.
- Independent, so multiply: 4/7 × 4/7 = 16/49.
- Answer: 16/49
Interactive practice
Free, no account required — answer on screen or print it.
Common mistakes
What learners typically get wrong, and how to fix it.
Writes probability as a ratio like 3:5.
Correction: Use a fraction, decimal or percentage.
Adds probabilities for 'and' events.
Correction: 'And' means multiply when events are independent.
Teacher tips
- · Run real experiments with dice and compare to theory.
Parent tips
- · Talk about the chance of rain from the forecast.
Real-life applications
- · Weather forecasts, games, insurance.
Assessment objectives
How mastery is evidenced, and which standards it maps to.
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Frequently asked
- Is this Grade 3 Conditional Probability quiz really free?
- Yes. Every quizzes on FreeMathWorksheet is free to use, print and share — no account, no paywall and no watermark.
- What should a learner already know before this?
- Start with Venn Diagrams, Tree Diagrams, Basic Probability. Each one has its own free lesson, worksheet and quiz.
- How is the quiz sequenced?
- Recognition first, then understanding, application, reasoning and finally mastery — the same ladder used across every free resource on the platform.
- What comes next after Conditional Probability?
- Move on to Basic Probability, which build directly on this idea.
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