Answer:

Step-by-step explanation:
Given that:
Speed of Wilmer up the hill =  km/min
 km/min
Time taken up the hill =  minutes
 minutes
Speed of Wilmer down the hill =  km/min
  km/min
Time taken up the hill =  minutes
 minutes
Distance can be calculated by multiplying the Speed with Time i.e. 
The formula for distance is given as:

Distance up the hill = 
Distance down the hill = 
It is well known that, the distance up the hill and down the hill will be same.
Putting both the values equal, we get:

 
        
             
        
        
        
To find your constant of variation, you just need to figure out what you multiply the x by in order to get f(x). In other words, what do you multiply the 3 by to get 6? What do you multiply the 7 by to get 14? Another way to think of it is to divide f(x) by the x to get your constant. 
        
             
        
        
        
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