I think it's C.
Let me know!
        
                    
             
        
        
        
Answer:
4:120
Step-by-step explanation:
for 120 student they would be 4 teacher needed per 30 student
4:120
 
        
             
        
        
        
5 Bc u divide 15 by 3 to get 5
        
                    
             
        
        
        
2/5 + 1/2 = 0.9 
0.9 in fraction form is 9/10! 
Hope this helps!
        
                    
             
        
        
        
The answer will be 
x=root 121
x=11