During an (very) early morning Calculus class you briefly shut your eyes, presumably to concentrate even harder on differential equations. When you open them you find that you have been magically transported to a beautiful tropical beach in 85 degree weather. Someone brings you a cold pina colada (initially at 35 degrees). Since you are not of legal drinking age, you (of course) don't drink it but just let it sit there on the beach and warm up. After 15 minutes it has warmed up to 40 degrees; when will it warm up to 50 degrees?