For .4 shade 4 squares, for .04 shade a bit less than half a square
        
             
        
        
        
Inital value= 35,000
depreciation value= .10 or 10%
value after 4 yrs= 22,963.5
        
             
        
        
        
The vertex is a minimum point. The y value of the vertex is the lowest point it hits. The graph is going down, the vertex is the lowest point of it
        
             
        
        
        
64 is the answer and apparently it needs to be longer than 20 characters
        
                    
             
        
        
        
31 seconds it will take to get around without it stopping