Question 992345
The number of miles per gallon obtained with a new Prius is a function of the speed at which it is driven. Is this function increasing or decreasing on its domain? Explain. 

(I think the function of miles per gallon decreases on its domain; however, I am having a hard time expressing in a f(x)=.....) 
-----
f(x) = speed/x
-----
This function expresses speed and mph as indirectly related (as speed goes up
mpg does down).
cheers,
Stan H.
------