A cup of coffee has temperature 95 °C and takes 30 minutes to cool to 61 °C in a room with temperature 20 °C

A cup of coffee has temperature 95 °C and takes 30 minutes to cool to 61 °C in a room with temperature 20 °C. Use Newton’s Law of Cooling to show that the temperature of the coffee after t minutes is T(t) = 20 + 75e-kt where k ≈ 0.02.