Certain chemotherapy dosages depend on a patient's surface area. According to the Mosteller model, Upper S equals StartFractionStartRoothwEndRoot Over 60 EndFraction , where h is the patient's height in centimeters, w is the patient's weight in kilograms, and S is the approximation to the patient's surface area in square meters. Assume that Kim's height is a constant 165 cm, but she is losing weight. If she loses 3 kg per month, how fast is her surface area decreasing at the instant she weighs 72 kg?