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Ex 13.5
Ex 13.5, 2 Deleted for CBSE Board 2023 Exams
Ex 13.5, 3 Important Deleted for CBSE Board 2023 Exams
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Ex 13.5, 5 Deleted for CBSE Board 2023 Exams
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Ex 13.5, 12 Deleted for CBSE Board 2023 Exams
Ex 13.5, 13 Important Deleted for CBSE Board 2023 Exams
Ex 13.5, 14 (MCQ) Important Deleted for CBSE Board 2023 Exams
Ex 13.5, 15 (MCQ) Important Deleted for CBSE Board 2023 Exams
Last updated at March 16, 2023 by Teachoo
Ex 13.5, 11 Find the probability of getting 5 exactly twice in 7 throws of a die. Let X : Number of times getting 5 Die thrown is a Bernoulli trial So, X has a binomial distribution P(X = x) = nCx n = number of times die is thrown = 7 p = Probability of getting 5 = 1 6 q = 1 p = 1 1 6 = 5 6 Hence, P(X = x) = 7Cx We need to find Probability of getting 5 twice i.e. P(X = 2) Putting x = 2 in (1) P(X = 2) = 7C2 1 6 2 5 6 7 2 = 7! 7 2 ! 2 ! 1 6 2 5 6 5 = 7 ! 5 ! 2 ! 1 6 6 5 6 5 = 7 6 5 ! 5 ! 2 ! . 6 . 6 5 6 5 = 7 2 1 6 5 6 2 = 7 12 5 6 5 Required Probability =