Okay, so we know a number of students and the amount of girls as a bracket. So what we have to do now is multiply them with each other.
28 *4/7 = 16
So there are 16 girls in Mr. Chang´s class.
You can also determine the boys by - the students with the girls:
28-16=12 boys
Have a nice day :D
        
                    
             
        
        
        
GIVEN
1) Females outnumber males by 3 to 2.
2) There are 1770 people in the city.
SOLUTION
Let the number of males be x and the number of females y. Therefore, the total number of people can be written to be:

If there are 3 females for every 2 males, we have that:

We can substitute equation (2) into equation (1) and solve for y:

Dividing both sides by 5, we have

There are 1062 females in the county.
 
        
             
        
        
        
Lol I don’t understand that language