Question

There are 40 people at a reception for international students. The students, boys and girls, are from Peru and China. 18 of all the students are boys, and 12 of all the students are Peruvian. 7 of the Peruvians are girls. Given that a student is a girl, what is the probability that she is Peruvian? A Venn diagram will help you to answer this question.

Answer 1

@amistre64

Answer 2

@mathmate

Answer 3

Have you made the Venn diagram?

Answer 4

If you are familiar with contingency tables, it is preferred over Venn diagram, because the variables are complementary.

This is a conditional probability problem. Have you worked with conditional probabilities before?