12. (4.1, 4.4) Suppose hot coffee at 969 C is brought into a room with a constant temperature of 219 C and reads 879 C after t = 6 minutes. Begin with the equation: T(t)= T env + [T(0)-7;W]e'\" - T(t) is the temperature of the thermometer as a function of time 1', Tem, is the temperature of the environment (i. e. the room) and k is a constant. a. (5 points) Begin by calculating the decay constant k. b. (5 points) What's the approximate temperature of the coffee after 18 minutes