Probability Tree Diagrams
Learn how to draw and use probability tree diagrams to work out probabilities step by step. Letโs get started! ๐

Video Lesson
Watch and learn the basics
Flashcards
Review key concepts visually
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๐๏ธ What Is a Probability Tree Diagram?
- A probability tree diagram shows all possible outcomes step by step.
- It is used for two-stage events, like drawing one ball at a time.
๐๏ธ Drawing the Probability Tree Correctly
- Write fractions on every branch so probabilities are clear.
- After the first outcome, update the probabilities for what is left.
๐๏ธ Finding the Probability of a Single Outcome
- You multiply the probabilities along one path.
- This gives the probability of one specific result.
๐๏ธ Finding the Probability of a Combined Event
- A combined event means more than one path fits the question.
- You add the probabilities of paths like redโred and blueโblue.
๐๏ธ Probability of At Least One Event Happening
- You can add all paths where the event happens.
- Or do 1 โ probability of the opposite to save time and check your answer.
Practice Questions
Test your understanding
Interactive Activity
Use a tree diagram to visualize how probabilities are calculated.
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