9.10
+2.53
————
 11.63
Just add the rows from the top to the bottom
        
             
        
        
        
100% of the original number
        
             
        
        
        
The correct equation that models for this problem is x over y or x/y.
Let the following values be:
x - would be the money or commissions that Duncan earned.
y - would be the 20 percent that he gives his assistant