3/7 of a class are boys. What fraction of the class consists of girls if there are 28 girls, how many boys are there in the class.
Fraction of girls:
1 - 3 / 7 = 7 / 7 - 3 / 7 = 4 / 7
x = numbers of sudents
there are 28 girls
4 / 7 x = 28
Multiply both sides by 7
4 x = 196
x = 196 / 4 = 49
49 students there in the class.
3 / 7 of 49 are boys
3 • 49 / 7 = 21 boys
OR
boys / girls = 3 / 4
3 • 28 / 4 = 21 boys
No response
To find out the fraction of the class that consists of girls, we need to first determine the total number of students in the class.
Since we know that 3/7 of the class are boys, we can set up a proportion using the information provided. Let's represent the total number of students as "x":
(3/7) = (number of boys)/(x)
To solve for the number of boys, we can cross-multiply:
3x = 7 * (number of boys)
Now, we are given that there are 28 girls. Since the total number of students in the class is x, the fraction of girls in the class is:
28/x
We can set up another proportion using this information:
(28/x) = (number of girls)/(x)
To solve for the number of girls, we again cross-multiply:
28x = (number of girls) * x
Since the fraction of girls is given, we can substitute the expression for the fraction of girls:
28x = (28/x) * x
Simplifying, we get:
28x = 28
Dividing both sides by 28, we find:
x = 1
Therefore, there is 1 boy in the class.