# Ex 13.5, 12 - Chapter 13 Class 12 Probability

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Ex 13.5, 12 Find the probability of throwing at most 2 sixes in 6 throws of a single die. Let X : be the number six we get on 5 throws Throwing a pair of die is a Bernoulli trial So, X has binomial distribution P(X = x) = nCx Where n = number of times die is thrown = 6 p = Probability of getting a six = 1 6 q = 1 1 6 = 5 6 Hence, P(X = x) = 6Cx We need to find probability of throwing at most 2 sixes in 6 throws of a single die. i.e. P(X 2) P(X 2) = P(X = 0) + P(X = 1) + P(X = 2) = 6C0 1 6 0 5 6 6 +6C1 1 6 1 5 6 5 +6C2 1 6 2 5 6 4 = 1 1 5 6 6 + 6 1 6 5 6 5 + 15 1 6 2 5 6 4 = 5 6 6 + 5 6 5 + 15 1 36 5 6 4 = 5 6 6 + 5 6 5 + 5 12 5 6 4 = 5 6 4 5 6 2 + 5 6 + 5 12 = 5 6 4 25 36 + 5 6 + 5 12 = 5 6 4 25 + 30 + 15 36 = 5 6 4 70 36 = So, the required Probability is 35 18 5 6 4

Chapter 13 Class 12 Probability

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Davneet Singh

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.