Answer:
Other options C. is the correct answer
Of the 4 people who have a sister, 2 of these also have a brother.
Explanation:
P(B|A)=P(A∩B)P(A)
It is given that P(B|A)= 0.5
From the given ven diagram,
A consists of {Davis, Kari, Chu, Evan}
B consists of {Adam,Bucci,Lyle,Chu,Evan}
A ∩ B = {Chu,Evan}
Possible outcomes of A =4
possible out comes of B = 5
possible out comes A ∩ B = 2
P(B|A)=P(A∩B)P(A) = 2/4 = 1/2 =0.5
It means that, Of the 4 people who have a sister, 2 of these also have a brother.
Other options C. is the correct answer