# Ex 13.2, 9 - Chapter 13 Class 12 Probability

Last updated at Dec. 8, 2016 by Teachoo

Last updated at Dec. 8, 2016 by Teachoo

Transcript

Ex 13.2, 9 (Method 1) If A and B are two events such that P (A) = 14 , P (B) = 14 and P(A ∩ B) = 18 , find P (not A and not B). Given, P(A) = 14 , P(B) = 12 & P(A ∩ B) = 18 P(not A & not B) = 1 – P(A or B) = 1 – P(A ∪ B) = 1 – [P(A) + P(B) – P(A ∩ B)] = 1 – 14 + 12 – 18 = 1 – 28 + 48 – 18 = 1 – 58 = 𝟑𝟖 Ex 13.2, 9 (Method 2) If A and B are two events such that P (A) = 14 , P (B) = 14 and P(A ∩ B) = 18 , find P (not A and not B). Given, P(A) = 14 , P(B) = 12 & P(A ∩ B) = 18 P(not A & not B) = P(A’ ∩ B’) = P(A ∪ B)’ = 1 – P(A∪B) P(A ∪ B) = P(A) + P(B) – P(A ∩ B) = 14 + 12 – 18 = 28 + 48 – 18 = 58 ∴ P(not A & not B) = 1 – 58 = 𝟑𝟖

Chapter 13 Class 12 Probability

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Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.