Step-by-step explanation:
$ 3750  = truck rental;   $125 per ton of sugar transported
 
C is cost;  S is number of tons transported
 
Equation relating C to S would be a linear equation like y = mx + b
 
C = 125S + $3750
 
This equation would be graphed in the first quadrant only
 
you would start with your y-intercept at (0, 3750)
 
As x increases by 1, your y increases by 125 yielding these points:
 
(1, 3875)  (2, 4000)  (3, 4125)  etc.  
 
This shows that for each increase by one ton of sugar, the cost goes up $125