Question

£ represents 29 students in class

B represents students who have a brother
S represents students who have a sister
a) One student from the class is chosen at random. What is the probability that the student has a sister?
b)One of the students who has a brother is chosen at random. What is the probability that this student has a sister?​

Answer 1

a) 14/29

b) 4/11

Explanation:

You forgot to add the Venn diagram

7+4+2x+X+3 =29

14 +3x= 29

3x = 15

X = 5

2*5=10

10+4=14

5+3=8

14/29

I hope this helps you :D

Have a good day

Answer 2

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

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