A small class has 10 students 3 of whom are girls and 7 of whom are boys. The teacher is going to choose two of the students at random. What is the probibility that the teacher will choose two girls? Write your answer as a fraction in simplest form.
2/10 - 1/5 because if the teacher wants 2 students and there's 3 girls and 7 boys, the probability of picking 2 girls is 2/10 which is 1/5 in simplest form