Answer:
a) One student from the class is chosen at random. What is the probability that the student has a sister?
S/£
b)One of the students who has a brother is chosen at random. What is the probability that this student has a sister?
BS/£²
Step-by-step explanation:
In the question, we are given the following values:
£ represents 29 students in class = Total number of students in the class.
B represents students who have a brother
S represents students who have a sister
The formula for probability = Number of events ÷ Number of possible outcomes.
a) One student from the class is chosen at random. What is the probability that the student has a sister?
Number of events = Number of students that have a sister = S
Number of possible outcomes = £ represents 29 students in class
The probability that the student has a sister = S/£
b)One of the students who has a brother is chosen at random. What is the probability that this student has a sister?
This is calculated as
The Probability of Students that have a brother and a sister = Probability of students that have a brother × Probability of student that have a sister.
Number of students that have a brother = B
Number of students that have a sister = S
The Probability of Students that have a brother and a sister = B/£ × S/£
= BS/£²
