Jash exercises at the gym 3 ¾ hours a week. He spends ⅖ of his time at the gym lifting weights. How many hours a week does josh spend lifting weights at the gym

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.