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?
Has a brother Does not have a brother
Has a sister 6 7
Does not have a sister 3 5
To find the probability that a student chosen randomly from the class has a brother and a sister, we first need to find how many students have both a brother and a sister. From the given data table, there are 6 students who have a brother and a sister.
The total number of students in the class is 6 + 7 + 3 + 5 = 21.
Therefore, the probability that a student chosen randomly from the class has a brother and a sister is:
Probability = Number of students with a brother and a sister / Total number of students
Probability = 6 / 21
Probability = 2 / 7
Therefore, the probability that a student chosen randomly from the class has a brother and a sister is 2/7 or approximately 0.2857.