Events of a random experiment — A/L Combined Mathematics

How do I practise Events of a random experiment?

1 question with a worked solution

Check before you answer: Sample Space Specification: Listing or describing all elements of the sample space S with proper set bracket notation.

1. Two events A and B in a sample space S are mutually exclusive (disjoint). If P(A) = 0.35 and P(B) = 0.45, what is the probability P(A ∪ B)?
   1. A) 0.1575
   2. B) 0.6425
   3. C) 0.10
   4. D) 0.80
   Check my answer

   Correct answer: D) 0.80

   For mutually exclusive events, they cannot occur simultaneously: A ∩ B = ∅ => P(A ∩ B) = 0. By the addition rule of probability: P(A ∪ B) = P(A) + P(B) - P(A ∩ B) = 0.35 + 0.45 - 0 = 0.80.

   Show worked solution

   Step 1: Mutually exclusive => P(A ∩ B) = 0. Step 2: P(A ∪ B) = P(A) + P(B) = 0.35 + 0.45 = 0.80. Answer: 0.80.
   Modelled on: the A/L Combined Mathematics examination pattern

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Where does Events of a random experiment fit in the syllabus?

Year 2 · Term 3