Chapter 13 Class 12 Probability

Class 12
Important Questions for exams Class 12

### Transcript

Ex 13.1, 10 A black and a red dice are rolled. (a) Find the conditional probability of obtaining a sum greater than 9, given that the black die resulted in a 5.Since both dies are rolled S = We need to find the Probability of obtaining a sum greater than 9, given that the black die resulted in 5 Let E : Sum of numbers greater than 9 F : 5 appeared on the black die We need to find P(E|F) Event E E = {(4, 6), (5, 5), (6, 4), (5, 6), (6, 5) , (6, 6)} P(E) = 6/36 Event F F = {(5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6)} P(F) = 6/36 Also, E ∩ F = {(5, 5), (5, 6)} So, P(E ∩ F) = 2/36 Now, P(E|F) = (𝑃(𝐸 ∩ 𝐹))/(𝑃(𝐹)) = (2/36)/(6/36) = 2/6 = 𝟏/𝟑 ∴ Required probability is 1/3

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#### Davneet Singh

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.