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  1. Chapter 16 Class 11 Probability
  2. Serial order wise

Transcript

Misc 8 From the employees of a company, 5 persons are selected to represent them in the managing committee of the company. Particulars of five persons are as follows: A person is selected at random from this group to act as a spokesperson. What is the probability that the spokesperson will be either male or over 35 years? Total number of persons = 5 So, n(S) = 5 Probability spokesperson is male Let A be the event that person selected is male There are 3 males So, n(A) = 3 Probability spokesperson is male = P(A) = (๐‘›(๐ด))/(๐‘›(๐‘†)) = 3/5 Probability spokesperson is over 35 years old Let B be the event that person selected is over 35 There are 2 person over 35 years old So, n(B) = 2 Probability spokesperson is over 35 years old = P(B) = (n(B))/(n(S)) = 2/5 We need to find probability that the spokesperson will be either male or over 35 year i.e. P(A โˆช B) We know that P(A โˆช B) = P(A) +P(B) โ€“ P(A โˆฉ B) To find P(A โˆช B), we must find P(A โˆฉ B) first P(A โˆฉ B) Probability that spokesperson is male & over 35 years old Here, 1 person is both male & over 35 years old So, n(A โˆฉ B) = 1 P(A โˆฉ B) = (๐‘›(๐ด โˆฉ ๐ต))/(๐‘›(๐‘†)) = 1/5 Now, P(A โˆช B) = P(A) +P(B) โ€“ P(A โˆฉ B) = 3/5 + 2/5 โ€“ 1/5 = (3 + 2 โˆ’ 1)/5 = 4/5 Hence Probability that the spokesperson will be either male or over 35 year = P(A โˆช B) = ๐Ÿ’/๐Ÿ“

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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.