The chance of randomly selecting someone from this group with a brother given that they have a sister is given by;
Option A; P(Brother|Sister) = 12
From the given venn diagram, we see that;
Number of students that had brothers; n(B) = 9
Number of Students that had brothers and sisters; n(B ∩ S)= 5
Number of students that had sisters; n(S) = 12
Number of students that didn't have any sibling; n(A' ∪ B') = 8
Now, we want to find P(B | S). This is a conditional probability because we are told that it represents the chance of randomly selecting someone from this group with a brother given that they have a sister and the formula according to sets is;
P(B | S) = (P(B ∩ S))/P(S)
Since they all have same denominators, then we can write as;
P(B | S) = 5/12
Read more at; https://brainly.com/question/16027295
