Probability = (favourable outcomes) / (total outcomes).
Key points
- P(A) = favourable / total
- 0 ≤ P(A) ≤ 1
- P(not A) = 1 - P(A)
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WAEC tip
Draw a sample space or tree diagram for multi-event questions.
Practise this
A bag has 4 red and 6 blue balls. Find P(red) and P(not red).
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