a car is traveling at a constant speed. it travels 3 2/1 miles in 5 1/4 minutes. how many minutes will it take the car to go 70miles

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.