When you have 3 for every 7, you divide
450 divided by 3
150
        
             
        
        
        
Answer: 48
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
Girls in Mr. Chang's class: 28 - 21 ; # girl students = # total students - # boy students ; 7 girl students.
Boys in Mr. Chang's class: 28 - 7 ; # boy students = # total students - girl students ; 21 boy students.
 
        
             
        
        
        
I'm sorry idk how to do it
        
             
        
        
        
3 because the numbers for x are all different