In a class of students, the following data table summarizes how many students have a brother or a sister. What is the probability that a student chosen randomly from the class has a brother and a sister?

Question

Has a brother Does not have a brother
Has a sister 7 3
Does not have a sister 9 8

Answer 1

Firstly, we need to find the total number of students in the class by summing up all the values in the table.

Total number of students = 7 + 3 + 9 + 8 = 27

Next, we need to determine the number of students who have both a brother and a sister. From the table, this value is 7.

Therefore, the probability that a student chosen randomly from the class has a brother and a sister is:

Probability = Number of students with brother and sister / Total number of students
Probability = 7 / 27
Probability = 0.259 or 25.9%

So, the probability that a student chosen randomly from the class has a brother and a sister is 25.9%.