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Free Grade 3 Introducing Conditional Probability Common Errors Quizzes

Free Grade 3 quizzes for Introducing Conditional Probability Common Errors: 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.

Price

Free

Difficulty

Core

Estimated time

15 min

Total marks

24

Learning objectives

Every objective is checkable, and each one maps to an activity and an assessment.

  • RememberIdentify introducing conditional probability common errors

    Identify introducing conditional probability common errors accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • UnderstandExplain introducing conditional probability common errors

    Explain introducing conditional probability common errors accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • ApplyCalculate introducing conditional probability common errors

    Calculate introducing conditional probability common errors accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • AnalyseCompare introducing conditional probability common errors

    Compare introducing conditional probability common errors 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 Introducing Conditional Probability Common Errors works

Probability measures how likely something is, from 0 (impossible) to 1 (certain). P(event) = favourable outcomes ÷ total outcomes. For independent events, multiply.

Key wordsprobabilityoutcomeeventindependentcertainimpossible

12 practice questions

Easy to hard, 24 marks in total. Try them first, then open the answers.

  1. 1.A bag has 4 red, 6 blue and 0 green counters. One is picked at random. Find P(red).[1]
  2. 2.A bag has 2 red, 6 blue and 4 green counters. One is picked at random. Find P(red).[1]
  3. 3.A bag has 3 red, 8 blue and 4 green counters. One is picked at random. Find P(red).[1]
  4. 4.A bag has 4 red, 3 blue and 1 green counters. One is picked at random. Find P(red).[1]
  5. 5.A bag has 7 red, 2 blue and 3 green counters. One is picked at random. Find P(red) and P(not red).[2]
  6. 6.A bag has 3 red, 5 blue and 2 green counters. One is picked at random. Find P(red) and P(not red).[2]
  7. 7.A bag has 3 red, 4 blue and 1 green counters. One is picked at random. Find P(red) and P(not red).[2]
  8. 8.A bag has 3 red, 4 blue and 5 green counters. One is picked at random. Find P(red) and P(not red).[2]
  9. 9.A bag has 1 red and 5 blue counters. Two are picked with replacement. Find P(both red).[3]
  10. 10.A bag has 1 red and 7 blue counters. Two are picked with replacement. Find P(both red).[3]
  11. 11.A bag has 7 red and 1 blue counters. Two are picked with replacement. Find P(both red).[3]
  12. 12.A bag has 6 red and 8 blue counters. Two are picked with replacement. Find P(both red).[3]
Show answers and working
  1. 1. P(red) = 2/5

    Total counters = 10. P(red) = 4/10 = 2/5.

  2. 2. P(red) = 1/6

    Total counters = 12. P(red) = 2/12 = 1/6.

  3. 3. P(red) = 1/5

    Total counters = 15. P(red) = 3/15 = 1/5.

  4. 4. P(red) = 1/2

    Total counters = 8. P(red) = 4/8 = 1/2.

  5. 5. P(red) = 7/12, P(not red) = 5/12

    Total counters = 12. P(red) = 7/12 = 7/12. P(not red) = 1 − 7/12 = 5/12.

  6. 6. P(red) = 3/10, P(not red) = 7/10

    Total counters = 10. P(red) = 3/10 = 3/10. P(not red) = 1 − 3/10 = 7/10.

  7. 7. P(red) = 3/8, P(not red) = 5/8

    Total counters = 8. P(red) = 3/8 = 3/8. P(not red) = 1 − 3/8 = 5/8.

  8. 8. P(red) = 1/4, P(not red) = 3/4

    Total counters = 12. P(red) = 3/12 = 1/4. P(not red) = 1 − 1/4 = 3/4.

  9. 9. 1/36

    P(red) = 1/6 each time. Independent, so multiply: 1/6 × 1/6 = 1/36.

  10. 10. 1/64

    P(red) = 1/8 each time. Independent, so multiply: 1/8 × 1/8 = 1/64.

  11. 11. 49/64

    P(red) = 7/8 each time. Independent, so multiply: 7/8 × 7/8 = 49/64.

  12. 12. 9/49

    P(red) = 6/14 each time. Independent, so multiply: 6/14 × 6/14 = 9/49.

Worked examples

Easy example

A bag has 6 red, 5 blue and 1 green counters. One is picked at random. Find P(red).

  1. Total counters = 12.
  2. P(red) = 6/12 = 1/2.
  3. Answer: P(red) = 1/2
Medium example

A bag has 2 red, 7 blue and 4 green counters. One is picked at random. Find P(red) and P(not red).

  1. Total counters = 13.
  2. P(red) = 2/13 = 2/13.
  3. P(not red) = 1 − 2/13 = 11/13.
  4. Answer: P(red) = 2/13, P(not red) = 11/13
Hard example

A bag has 5 red and 7 blue counters. Two are picked with replacement. Find P(both red).

  1. P(red) = 5/12 each time.
  2. Independent, so multiply: 5/12 × 5/12 = 25/144.
  3. Answer: 25/144

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.

CAMBRIDGE CAM-786.1 — Mapped statement covering Introducing Conditional Probability Common Errors.NATIONAL-CURRICULUM NAT-230.2 — Mapped statement covering Introducing Conditional Probability Common Errors.

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Frequently asked

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What should a learner already know before this?
Start with Introducing Conditional Probability Word Problems, Introducing Conditional Probability Techniques, Venn Diagrams. 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 Introducing Conditional Probability Common Errors?
Move on to Working with Conditional Probability, Conditional Probability in Context, which build directly on this idea.

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