4. A body of a murder victim was discovered at 6pm. Police officers measured the body temperature at 6.10pm and then again at 7.10pm; the temperature readings were 30"C and 27"C correspondingly. The temperature of the building is maintained by an air conditioning system at the constant 24"C. Assuming the victim had normal temperature of 37"C at the time of the murder, what time did the murder happen? Use Newton's law of cooling dT dt = k(M - T). where T is the temperature of the body, M is the temperature of the environment and k is a proportionality coefficient. (Hint: take 6.10pm as t = 0)