# Ex 13.3, 4

Last updated at March 11, 2017 by Teachoo

Last updated at March 11, 2017 by Teachoo

Transcript

Ex 13.3, 4 In answering a question on a multiple choice test, a student either knows the answer or guesses. Let 34 be the probability that he knows the answer and 14 be the probability that he guesses. Assuming that a student who guesses at the answer will be correct with probability 14. What is the probability that the student knows the answer given that he answered it correctly? Let A : student know the answer B : student guesses C : student answers correctly We need to find the Probability that the student knows the answer, if he answered it correctly i.e. P(A|C) P(A|C) = P(A) . P(C|A) P(B) . P(C|B) + P(A) P(C|A) Putting values in formula, P(A|C) = 34 × 1 14 × 14 + 14 × 1 = 14 × 3 14 14 +3 = 3 14 + 3 = 3 134 = 1213 Therefore, required probability is 𝟏𝟐𝟏𝟑

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Ex 13.3, 2 Important

Ex 13.3, 4 Important You are here

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Ex 13.4, 3 Important

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Example 35 Important

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Misc 6 Important

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Important Question for exams Class 12

- Chapter 1 Class 12 Relation and Functions
- Chapter 2 Class 12 Inverse Trigonometric Functions
- Chapter 3 Class 12 Matrices
- Chapter 4 Class 12 Determinants
- Chapter 5 Class 12 Continuity and Differentiability
- Chapter 6 Class 12 Application of Derivatives
- Chapter 7 Class 12 Integrals
- Chapter 8 Class 12 Application of Integrals
- Chapter 9 Class 12 Differential Equations
- Chapter 10 Class 12 Vector Algebra
- Chapter 11 Class 12 Three Dimensional Geometry
- Chapter 12 Class 12 Linear Programming
- Chapter 13 Class 12 Probability

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He provides courses for Mathematics from Class 9 to 12. You can ask questions here.