Brewed coffee is often too hot to drink right away. You can cool it with an ice cube, but this dilutes it. Or you can buy a device that will cool your coffee without dilution - a 270g aluminum cylinder that you take from your freezer and place in a mug of hot coffee. If the cylinder is cooled to -20 C, a typical freezer temperature, and then dropped into a large cup of coffee (essentially water, with a mass of 500 g at 85 C, what is the final temperature of the coffee?