So the derivative of 20 times something with respect to time is going to be the derivative of 20 times something with respect to the something, which is just 20. That's the derivative of 20x with respect to x times dx, the derivative of x with respect to t, is equal to. Now, over here, we're going to have to break out a little bit of the product rule. So first, we want to figure out the derivative of x with respect to time. So the derivative of x with respect to time. So the derivative of the first thing times the second thing times y, plus just the first thing times the derivative of the second thing. So the derivative of y with respect to t is just dy dt.