# Misc 2 - Chapter 13 Class 12 Probability

Last updated at Feb. 15, 2020 by Teachoo

Last updated at Feb. 15, 2020 by Teachoo

Transcript

Misc 2 A couple has two children, (i) Find the probability that both children are males, if it is known that at least one of the children is male.A Couple has two children, Let boy be denoted by b & girl be denoted by g So, S = {(b, b) ,(b, g),(g, b), (g, g)} We need to find probability that both children are males, if known that at least one of children is male Let E : Both children are males F : At least one child is male We need to find P(E|F) Also, E ∩ F = {(b, b)} P(E ∩ F ) = 1/4 P(E|F) = (𝑃(𝐸 ∩ 𝐹))/(𝑃(𝐹)) = (1/4)/(3/4) = 1/3 ∴ Required Probability is 𝟏/𝟑 E : Both children are males E = {(b, b)} P(E) = 1/4 F : At least one child is male F = {(b, g), (g, b), (b, b)} P(F) = 3/4 Misc 2 A couple has two children, (ii) Find the probability that both children are females, if it is known that the elder child is a femaleHere, S = {(b, b) ,(b, g),(g, b), (g, g)} A We need to find the probability that both children are females, if from that the elder child is a female. Let E : both children are females F : elder child is a female We need to find P(E|F) E : both children are females E = {(g, g)} P(E) = 1/4 F : elder child is a female F = {(g, b), (g, g)} P(F) = 2/4=1/2 Also, E "∩" F = {(g, g)} So, P(E "∩" F) = 1/4 Now, P(E|F) = (𝑃(𝐸 ∩ 𝐹))/(𝑃(𝐹)) = (1/4)/(1/2) = 1/2

Miscellaneous

Misc 1

Misc 2 Important You are here

Misc 3

Misc 4 Deleted for CBSE Board 2021 Exams only

Misc 5 Important Deleted for CBSE Board 2021 Exams only

Misc 6 Important Deleted for CBSE Board 2021 Exams only

Misc 7 Important

Misc 8 Important

Misc 9 Important Deleted for CBSE Board 2021 Exams only

Misc 10 Important

Misc 11 Important

Misc 12

Misc 13 Important

Misc 14 Important

Misc 15 Important

Misc 16 Important

Misc 17 Important

Misc 18

Misc 19

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.