A science class has 3 girls and 7 boys in the seventh grade and 5 girls and 5 boysin the eighth grade. The teacher randomly selects a seventh grader and an eighth grader from the class for a competition. What is the probability that the students she selects are both girls?

3/10 * 5/10

Combined property is what I need :)

To find the probability that the teacher selects two girls, you need to determine the total number of possible outcomes and the number of favorable outcomes.

Total number of possible outcomes: The teacher can choose one student from the seventh grade and one student from the eighth grade. Since there are 10 students in the seventh grade and 10 students in the eighth grade, the total number of possible outcomes is 10 * 10 = 100.

Number of favorable outcomes: To select two girls, the teacher needs to choose one girl from the seventh grade (3 girls) and one girl from the eighth grade (5 girls). Therefore, the number of favorable outcomes is 3 * 5 = 15.

Probability = Number of favorable outcomes / Total number of possible outcomes
Probability = 15 / 100
Probability = 0.15 or 15%