Example 14 - Chapter 13 Class 12 Probability

Last updated at April 16, 2024 by

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Example 14 If A and B are two independent events, then the probability of occurrence of at least one of A and B is given by 1– P(A′) P(B′) Since events A and B are independent ∴ P(A ∩ B) = P(A) . P(B) Now, Probability of occurrence of at least one of A and B = Probability of occurrence of only A + Probability of occurrence of only B + Probability of occurrence of A and B = Probability of occurrence of A or B = P(A ∪ B) = P(A) + P(B) – P(A ∩ B) Since A & B are independent Putting P(A ∩ B) = P(A) . P(B) = P(A) + P(B) – P(A) . P(B) = P(A) + P(B) [ 1 – P(A) ] = P(A) + P(B) . P(A’) = 1 – P(A’) + P(B) . P(A’) = 1 – P(A’) [ 1 – P(B) ] = 1 – P(A’) . P(B’) Thus, P(at least one of A & B) = 1 – P(A’) P(B’) Hence Proved

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.