Dr. Van Nostrand would like to make a drink for his infant son. The recipe: a half cup of hot tea(weakly brewed) and a half cup of cold milk.9Sugar is also added, but we'll ignore that here.)

Now suppose that the hot tea is poured into the cup first. Then, due to an impending diaper change, Dr. Van Nostrand must decide whether to add the cold milk immediately or in 5 minutes. Which method will yield the coolest drink?

Use Newton's law of citing, assuming the same k value for the tea, milk, and tea-milk mixture. Also assume that mixing occurs instantly, and that the milk is kept in the fridge until used.