Question

A math class has 3 girls and 9 boys in the seventh grade and 7 girls and 3 boys in the eighth grade. The teacher randomly selects a seventh grader and an

eighth grader from the class for competition. What is the probability that the students she selects are both girls?
Write your answer as a fraction in simplest form.

Answer 1

7/40

Explanation:

There are 3 girls+9 boys = 12 students in the 7th grade

P (girl in 7th grade) = girls/ total

= 3/12 = 1/4

There are 7 girls+3 boys = 10 students in the 8th grade

P (girl in 8th grade) = girls/ total

= 7/10

P(7th grade girl, 8th grade girl) = 1/4 * 7/10 = 7/40