We're being given the rate at which the volume of the water is changing with respect to time. So let's write that down. We're being given the rate at which the volume of the water is changing with respect to time. And we're being told. We're told that this is 1 cubic centimeter per second. And what are we trying to figure out? Well, we're trying to figure out how fast the height of the water is changing with respect to time.