The temperature of a body falls from 90°C to 70°C℃ in 5 minutes when placed in a surrounding of constant temperature 20°C. (a) Write down a differential equation for the rate at which the temperature of the body is decreasing.? [3] (b) Solve the differential equation for the temperature T, of the body at any time t. [4] [3] (c) Use your answer in question (b) to find the time taken for the body to become 50°C (d) What will be the temperature of the body after 20 minutes?
