15 = 3 parts
15 divided by 3 = 5
5 = 1 part
A calls for 5 parts
5 • 5 = 25
Answer: 25 Milliliters
        
             
        
        
        
15x-10=20
 +10 +10
15x=30
\15 /15
x=2
you add 10 to both -10 (they cancek eachother out) and 20 (equals 30) 
Then you divide 30 by 15 (equals 2) and 15 by 15 (they cancel eachother out) 
Then you get x=2
        
                    
             
        
        
        
Answer:
60ft
Step-by-step explanation:
I have not  done this kind of work in a while but if you scale each side of the square by 6 is should increase to a perimeter of 60ft