A boat can travel at an average speed of 10 miles per hour in still water. Traveling with a current, it can travel 6 miles in the same amount of time it takes to travel 4 miles upstream.

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.