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 and a sister?
Has a brother Does not have a brother
Has a sister 3 5
Does not have a sister 8 14

Answer 1

There are 3 students who have both a brother and a sister, out of 3+5+8+14 = 30 students total.
Probability = 3/30 = 1/10 = 0.1 = 10%.