Mutually Exclusive Events
Events A and B are mutually exclusive if they cannot occur together, meaning P(A ∩ B) = 0 and P(A ∪ B) = P(A) + P(B).
Real World
In the 2024 UK General Election, a constituency voter casting a ballot for Labour and simultaneously casting it for the Conservatives is impossible — these outcomes are mutually exclusive.
Exam Focus
Never confuse mutually exclusive with independent; if asked to distinguish them, state that mutually exclusive events cannot both occur whereas independent events do not affect each other.
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