A math class has 3 girls and 7 boys in the seventh grade and 2 girls and 2 boys in 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 boys?
Prob(boy from 7th grade) = 7/10
Prob(boy from 8th grade) = 2/4 = 1/2
Prob(2 boys) = (7/10)(1/2) = 7/20
answer yourself
To find the probability that the teacher selects two boys, 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 any student from the seventh grade (10 students) and any student from the eighth grade (4 students). Therefore, the total number of possible outcomes is 10 * 4 = 40.
Number of favorable outcomes:
To have two boys selected, the teacher needs to choose one boy from the seventh grade and one boy from the eighth grade. There are 7 boys in the seventh grade and 2 boys in the eighth grade. Therefore, the number of favorable outcomes is 7 * 2 = 14.
Probability:
The probability is the ratio of the number of favorable outcomes to the total number of possible outcomes. Therefore, the probability is 14/40 = 7/20.
So, the probability that the teacher selects two boys is 7/20.
A math class has 3 girls and 5 boys in the seventh grade and 2 girls and 2 boys in 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 boys?
A math class has girls and boys in the seventh grade and girls and boys in 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?
Write your answer as a fraction in simplest form.