A class of 21 students has 9 girls and 12 boys. What is the probability of a teacher randomly picking on a boy?
A. 3/4
B. 4/7
C. 3/7
D. 4/3
The correct answer is B. 4/7
Right.
how?
12 boys out of 21 = 12/21
Divide both by 3 to reduce and you get 4/7
That makes so much since. Thank you.
To find the probability of the teacher randomly picking on a boy, we need to determine the ratio of boys to the total number of students.
The total number of students in the class is 21.
The number of boys in the class is 12.
So, the probability of picking a boy is 12/21.
To simplify the fraction, we can divide both the numerator and the denominator by their greatest common divisor, which is 3.
12 ÷ 3 = 4
21 ÷ 3 = 7
Therefore, the probability of the teacher randomly picking on a boy is 4/7.
So, the correct answer is B. 4/7.