There are twice as many girls as boys in the fourth grade classes at Joe's school. There are a total of 81 fourth graders. How many boys and girls are there in the fourth grades
Let the number of boys be x.
Then the number of girls is 2x.
The total number of fourth graders is x + 2x = 81.
Combining like terms, we get 3x = 81.
Dividing both sides by 3, we get x = 27.
Therefore, there are 27 boys and 2 * 27 = <<27*2=54>>54 girls in the fourth grade. Answer: \boxed{27,54}.
To find the number of boys and girls in the fourth grade classes at Joe's school, we can set up an equation based on the given information.
Let's assume the number of boys is "x" and the number of girls is "2x" (since there are twice as many girls as boys).
According to the problem, the total number of fourth graders is 81. So we can write the equation:
x + 2x = 81
Combining like terms, we get:
3x = 81
To solve for x, the number of boys, we divide both sides of the equation by 3:
x = 81 / 3
x = 27
Therefore, there are 27 boys in the fourth grade classes.
To find the number of girls, we substitute the value of x back into the equation:
2x = 2 * 27
2x = 54
Therefore, there are 54 girls in the fourth grade classes.
In conclusion, there are 27 boys and 54 girls in the fourth grade classes at Joe's school.
Let's represent the number of boys as "x".
According to the problem, there are twice as many girls as boys, so the number of girls can be represented as "2x".
The total number of fourth graders is given as 81. Therefore, the sum of the number of boys and girls should equal 81:
x + 2x = 81
Combining like terms:
3x = 81
Now, solving for "x" by dividing both sides by 3:
x = 81 / 3
x = 27
So, there are 27 boys in the fourth grade.
To find the number of girls, we can substitute the value of "x" back into the expression for the number of girls ("2x"):
2x = 2 * 27
2x = 54
Therefore, there are 54 girls in the fourth grade.
In conclusion, there are 27 boys and 54 girls in the fourth grade.