# Ex 13.5, 10

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Ex 13.5, 10 A person buys a lottery ticket in 50 lotteries, in each of which his chance of winning a prize is 1100 . What is the probability that he will win a prize (a) at least once (b) exactly once (c) at least twice? Let X : Number of times he wins a prize Winning a prize on lottery is a Bernoulli trial So, X has a binomial distribution P(X = x) = nCx 𝒒𝒏−𝒙 𝒑𝒙 n = number of lotteries = 50 p = Probability of winning a prize = 1100 q = 1 – p = 1 − 1100 = 99100 Hence, ⇒ P(X = x) = 50Cx 𝟏𝟏𝟎𝟎𝒙 𝟗𝟗𝟏𝟎𝟎𝟓𝟎−𝒙 (a) Probability that he wins the lottery atleast once P (at least once) = P(X ≥ 1) = 1 − P (0) = 1 − 50C0 11000 9910050−0 = 1 − 1 × 1 × 9910050 = 1 − 9910050 (b) Probability that he wins the lottery exactly once P (exactly once) = P(X = 1) = 50C1 11001 9910050−1 = 50 × 1100 × 9910049 = 12 9910049 (c) Probability that he wins the lottery atleast twice P (atleast twice) = P(X ≥ 2) = 1 – [P(X = 0) + P(X = 1)] = 1 – 50C0 11000 9910050−0+ 50C1 11001 9910050−1 = 1 – 9910050+ 12 9910049 = 1 – 9910049 99100+ 12 = 1 – 9910049 99 + 50100 = 1 − 149100 9910049

Chapter 13 Class 12 Probability

Example 7
Important

Example 6 Important

Ex 13.1, 10 Important

Ex 13.1, 12 Important

Example 11 Important

Ex 13.2, 7 Important

Ex 13.2, 11 Important

Ex 13.2, 14 Important

Example 17 Important

Example 18 Important

Example 20 Important

Example 21 Important

Ex 13.3, 2 Important

Ex 13.3, 4 Important

Ex 13.3, 8 Important

Ex 13.3, 10 Important

Ex 13.3, 12 Important

Ex 13.3, 13 Important

Example 25 Important

Example 26 Important

Example 27 Important

Example 28 Important

Example 29 Important

Ex 13.4, 3 Important

Ex 13.4, 6 Important

Ex 13.4, 11 Important

Ex 13.4, 15 Important

Example 31 Important

Example 32 Important

Ex 13.5, 4 Important

Ex 13.5, 6 Important

Ex 13.5, 10 Important You are here

Ex 13.5, 13 Important

Example 35 Important

Example 36 Important

Misc 6 Important

Misc 9 Important

Misc 11 Important

Misc 13 Important

Misc 16 Important

Class 12

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 has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.