i think this is a systems of equations
putting this on a graph we have to equations:
y = 10x + 30
y = 20x
graph and find the intersection.
it has to be more than or equal to 3 miles i think for wreckomend
 
        
             
        
        
        
The answer would be (8/11,0) as the x-intercept
        
             
        
        
        
Answer:

Step-by-step explanation:
In 5 liters, there is 4% salt. 
Lets find liters of salt.
First, converting 4% to decimal (dividing by 100):
4% = 4/100 = 0.04
0.04 * 5 = 0.2
So, there is 0.2 liters of salt.
Now, x liters of water is added to total, so total is now:
5 + x
The concentration of salt will be amount of salt divided by amount of salt water solution.
Amount of salt = 0.2 (as seen above)
Amount of new salt water solution = x + 5
So, 
Concentration of salt in new solution is  
2nd choice is right.
 
        
             
        
        
        
I think is uh.. i think is uh carrot