Question

Conditional probabilities

Answer 1

Answer:

D) Of the 4 people who have a sister, 1 of them also has  a brother.

Step-by-step explanation:

P(B/A) indicates the probability of event B when event A has alredy occured.

Event A = The person has a sister.

Event B = The person has a brother.

So now P(B/A) means the probability of the person having sister who already have brother.

Hence choice "D) Of the 4 people who have a sister, 1 of them also has  a brother." is correct.