Complementary events
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Log in to continueUse “not” to find the outcomes outside an event and subtract its probability from one.
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The probability of event A is 1/5. What is the probability that A does not occur?
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Answer: 4/5
- A and not-A include all outcomes and cannot both occur in one trial.
- P(not A) = 1 − 1/5 = 4/5.
- 1 − 1/5 = 4/5.
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Curriculum reference
Victorian Curriculum F–10 Version 2.0
Pi Leo practice scope
Use “not” to find the outcomes outside an event and subtract its probability from one.
Read the official VCAA curriculum description (VC2M8P01)
These quizzes practise concepts within this topic. Multiple-choice answers alone do not demonstrate drawing, conducting an investigation or using a digital tool.
- VC2M8P01-C01Calculate complementary probabilities.
- VC2M8P01-C02Identify complementary outcomes in practical situations.
- VC2M8P01-C03Apply and explain complementary events using calculate and explain each step.
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Subskills
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Descriptor-derived subskills
- D01An event and everything elseCalculate complementary probabilities.
- D02Name the complement completelyIdentify complementary outcomes in practical situations.
- D03Calculate and explain each stepApply and explain complementary events using calculate and explain each step.