Suppose that the following function is used to model the monthly demand for bicycles:...

Suppose that the following function is used to model the monthly demand for bicycles:

In this formula, x represents the price (in dollars per gallon) of automobile gasoline and y represents the selling price (in dollars) of each bicycle. Furthermore, suppose that the price of gasoline t months from now will be

and the price of each bicycle will be

At what rate will the monthly demand for bicycles be changing six months from now?