Aforensic scientist is called to the scene of a murder. The temperature of the corpse is found to be 75◦F and one hour later the temperature has dropped to 70◦F. If the temperature of the room in which the body was discovered is a constant 68◦F, how long before the first temperature reading was taken did the murder occur? Assume that the body obeys Newton’s law of cooling, dT dt = β(T − TR), where T is the temperature of the corpse, β is a constant, and TR is room temperature.