A piece of rubber tubing maintains a cylindrical shape as it is stretched. At the instant that the inner radius of the tube is 2 millimeters and the height is 20 millimeters, the inner radius is decreasing at the rate of 0. 1 millimeter per second and the height is increasing at the rate of 3 millimeters per second. Which of the following statements about the volume of the tube is true at this instant? (the volume v of a cylinder with radius r and height h is v=πr2h. ).