A science class has 3 girls and
3 boys in the seventh grade and
4 girls and 1 boy 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?
Probability that the 7th grader is a boy = number of boys/number of students = 3 / ( 3 + 3 ) = 3 / 6 = 1 / 2
Probability that the 8th grader is a boy = number of boys/number of students = 1 /( 4 + 1 ) = 1 /5
Probability that both are boys = 1 / 2 * ( 1 / 5 ) = 1 / 10 = 0.1 = 10 %
prob (2 boys)
= 2 (3/6)(1/5)
= 1/5
I multiplied by 2 since it could be
boy from grade7 x boy from grade 8
or boy from grade8 x boy from grade 7
a science class has 5 girls and 3 boys in the seventh grader and 2 girls and 6 boys in the eight grader. the teacher randomly selects a seventh grader and a eight grader for a class competition. what is the probability that the students are both boys
To calculate the probability of selecting two boys, we first need to determine the total number of possible outcomes for selecting one student from each grade.
We have 3 boys in the seventh grade and 1 boy in the eighth grade. So the total number of possible outcomes is 3 * 1 = 3.
Next, we need to determine the number of favorable outcomes, which is the event of selecting two boys.
We have 3 boys in the seventh grade, so the probability of selecting a boy from the seventh grade is 3/6. Similarly, we have 1 boy in the eighth grade, so the probability of selecting a boy from the eighth grade is 1/5.
To find the probability of both events happening, we multiply the two probabilities:
P(Selecting a boy from seventh grade) = 3/6
P(Selecting a boy from eighth grade) = 1/5
P(Selecting both boys) = P(Selecting a boy from seventh grade) * P(Selecting a boy from eighth grade)
P(Selecting both boys) = (3/6) * (1/5)
P(Selecting both boys) = 3/30
P(Selecting both boys) = 1/10
Therefore, the probability that the teacher selects two boys is 1/10.