Newton's Law of Cooling States That the Rate at Which $^\circ$

Newton's Law of Cooling states that the rate at which a body changes temperature is proportional to the difference between its temperature and the temperature of the surrounding medium. Suppose that a body has an initial temperature of 250 $^\circ$ F and that after one hour the temperature is 200 $^\circ$ F. Assuming that the surrounding air is kept at a constant temperature of 72 $^\circ$ F, determine the temperature of the body at time $t$ .