Last updated at March 9, 2017 by Teachoo

Transcript

Ex16.3, 21 In a class of 60 students, 30 opted for NCC, 32 opted for NSS and 24 opted for both NCC and NSS. If one of these students is selected at random, find the probability that The student opted for NCC or NSS. There are 60 student in a class n(S) = 60 Let A be the event that a student opted for NCC & B be the event that a student opted for NSS Given that 30 students opted for NCC So, n(A) = 30 Probability of a student opted for NCC = P(A) = (n(A))/(n(S)) = 30/60 Also, 32 student opt NSS n(B) = 32 Probability of a student opt for NSS = P(B) = (n(B))/(n(S)) = 32/60 And 24 student for both NCC & NSS n(A ∩ B) = 24 Probability of opted for both NCC & NSS = P(A ∩ B) = (n(A ∩ B))/(n(S)) = 24/60 We need to find the probability that the student opted for NCC or NSS. i.e. P(A ∪ B) We know that P(A ∪ B) = P(A) + P(B) – P(A ∩ B) Putting values = 30/60 + 32/60 – 24/60 = (30 + 32 − 24)/60 = (62 − 24)/60 = 38/60 = 19/30 Hence, probability that the student opted for NCC or NSS.= P(A ∪ B) = 𝟏𝟗/𝟑𝟎 Ex16.3, 21 In a class of 60 students, 30 opted for NCC, 32 opted for NSS and 24 opted for both NCC and NSS. If one of these students is selected at random, find the probability that (ii) The student has opted neither NCC nor NSS. Probability student has opted neither NCC has NSS = P(A’ ∩ B’) = P (A ∪ B)’ = 1 – P (A ∪ B) Putting values = 1 – 19/30 = (30 − 19)/30 = 𝟏𝟏/𝟑𝟎 Ex16.3, 21 In a class of 60 students, 30 opted for NCC, 32 opted for NSS and 24 opted for both NCC and NSS. If one of these students is selected at random, find the probability that (iii) The student has opted NSS but not NCC. Probability student has opted NSS but not NCC = P(A’ ∩ B) = P(B) – P(A ∩ B) Putting values = 32/60 – 24/60 = (32 − 24)/60 = 8/60 = 𝟐/𝟏𝟓

Class 11

Important Question for exams Class 11

- Chapter 1 Class 11 Sets
- Chapter 2 Class 11 Relations and Functions
- Chapter 3 Class 11 Trigonometric Functions
- Chapter 4 Class 11 Mathematical Induction
- Chapter 5 Class 11 Complex Numbers
- Chapter 6 Class 11 Linear Inequalities
- Chapter 7 Class 11 Permutations and Combinations
- Chapter 8 Class 11 Binomial Theorem
- Chapter 9 Class 11 Sequences and Series
- Chapter 10 Class 11 Straight Lines
- Chapter 11 Class 11 Conic Sections
- Chapter 12 Class 11 Introduction to Three Dimensional Geometry
- Chapter 13 Class 11 Limits and Derivatives
- Chapter 14 Class 11 Mathematical Reasoning
- Chapter 15 Class 11 Statistics
- Chapter 16 Class 11 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 7 years. He provides courses for Mathematics and Science from Class 6 to 12. You can learn personally from here https://www.teachoo.com/premium/maths-and-science-classes/.