Question

For a certain class, the following data table compares how many students have a brother or a sister. What is the probability that a randomly chosen student from the class has a brother?
Has a brother Does not have a brother
Has a sister 7 3
Does not have a sister 10 2

Answer 1

There are 7 + 10 = 17 students who have a brother out of a total of 7 + 3 + 10 + 2 = 22 students.

Probability = 17/22 ≈ 0.7727 (77.27%).