A cup of coffee with cooling constant k = 0.06 min'1 is placed in a room at temperature 20C. How fast is the coffee cooling (in degrees per minute) when its temperature is T = 80C? (Give the absolute value of the cooling rate. Use decimal notation. Round your answer up to two decomal places, if necessary.) Use the Linear Approximation to estimate the change in temperature over the next 6 s when T = SO'C. (Give the absolute value of the temperature change. Use decimal notation. Round your answer up to three decomal places, if necessary.) If the coffee is served at a temperature of 90C, how long will it take to reach an optimal drinking temperature of 50' C? (Use symbolic notation and fractions where needed.) waiting time: min